Research on pheromone lures and traps for monitoring and management of the fall armyworm spodoptera frugiperda (j e smith) on maize in vinh phuc, vietnam 2020

The density of fall armyworm on the maize field of pheromone experiment in Vinh Phuc 2020 .... Number of male adult captured in different pheromone lure types in Vinh Phuc 2020 .... The

VIETNAM NATIONAL UNIVERSITY OF AGRICULTURE

IN VINH PHUC, VIETNAM 2020”

i

THE GUARANTEE

I hereby guarantee that this undergraduate thesis is my research work The graduation thesis research data and results are honest and have never been published The information cited in this graduation thesis has a clear origin

Any assistances in implementing this study has been appreciated

ii

ACKNOWLEDGEMENT

In order to complete the undergraduate thesis, in addition to my own endeavors, I have received enthusiastic support and guidance from teachers, family, and friends

First of all, I would like to express my earnest gratitude to Dr NGUYEN THI THU PHUONG, Department of Entomology, Vietnam National University of Agriculture directly instructed me wholeheartedly and helped me in the process of completing my graduation thesis

I would like to express my sincere thanks to all the teachers of the Department of Entomology, Vietnam National University of Agriculture for their support, making the best conditions for me to implement my graduation thesis

Finally, I would like to sincerely thank my family, relatives, friends who have helped and encouraged me throughout the process of doing the thesis

This thesis is hard to avoid shortcomings I hope to get the remarks of teachers and readers My sincere thanks!

Hanoi, March 4 th , 2021

Student

PHAM TRUNG KIEN

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TABLE OF CONTENT

THE GUARANTEE i

ACKNOWLEDGEMENT ii

TABLE OF CONTENT iii

LIST OF ABBREVIATION vi

LIST OF TABLE vii

LIST OF FIGURE viii

LIST OF DIAGRAM ix

ABSTRACT x

PART I: INTRODUCTION 1

1.1 Introduction 1

1.2 Objective and Requirement 2

1.2.1 Objectives 2

1.2.2 Requirements 2

PART II: LITERATURE REVIEW 3

2.1 Research over the World 3

2.1.1 Taxonomic Tree 3

2.1.2 Distribution 3

2.1.3 Symptoms 4

2.1.4 Damage 5

2.1.5 Description and Life Cycle 6

2.1.6 Host Range 8

2.1.7 Management 9

2.1.8 Female sex pheromone of fall armyworm 11

2.2 Research in Vietnam 14

2.2.1 Situation 14

2.2.2 Symptoms 16

2.2.3 Morphological and biological of fall armyworm 17

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2.2.4 Management 17

2.2.5 Sex pheromone application in Vietnam 18

PART III: MATERIAL AND METHOD 19

3.1 Objectives and Materials 19

3.2 Location and Time 19

3.3 Target 19

3.4 Methods 20

3.4.1 Field survey 20

3.4.2 Method of rearing insect in experiments of biological characteristic of S frugiperda 21

3.4.3 Method of investigation the method applied pheromone lures and traps on the field 23

3.4.4 Calculation methods 27

3.4.5 Data processing 28

PART IV: RESULTS AND DISCUSSION 29

4.1 Harmful symptoms of fall armyworm in Vinh Phuc, Hanoi 29

4.2 Morphological characteristic of fall armyworm 30

4.3 Biological characteristic of fall armyworm 35

4.3.1 Fall armyworm size 35

4.3.2 Development time 37

4.3.3 Food consuming ability 39

4.3.4 Mortality and sex ratio 40

4.4 Pheromone lure types experiment in Vinh Phuc 41

4.5 Pheromone trap types experiment in Vinh Phuc 44

4.6 Pheromone trap height experiment in Vinh Phuc 48

4.7 Pheromone trap distance experiment in Vinh Phuc 49

PART V: CONCLUSION 52

5.1 Conclusion 52

5.2 Recommendation 52

REFERENCES 53

v APPENDIX 57

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LIST OF ABBREVIATION

FAO Food and Agriculture Organization CABI Centre for Agriculture and Biosciences International FAW Fall armyworm

TM Treatment

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LIST OF TABLE

Table 2.1 Vietnam corn planted and FAW infected area from October 2019 to May 2020 16

Table 4.1 Head capsule width of larvae fall armyworm Spodoptera frugiperda 35

Table 4.2 Length, width and weight of pupa and wingspan ranged of male and

female adult fall armyworm Spodoptera frugiperda 36

Table 4.3 The development time of male and female adult fall armyworm 38

Table 4.4 Food consuming ability of larvae fall armyworm Spodoptera frugiperda

on maize 39Table 4.5 Mortality of fall armyworm in laboratory 40

Table 4.6 The density of fall armyworm on the maize field of pheromone

experiment in Vinh Phuc 2020 41Table 4.7 Number of male adult captured in different pheromone lure types in Vinh Phuc 2020 43Table 4.8 The density of fall armyworm on the maize field of pheromone trap colour and Chinese trap experiment compare to control in Vinh Phuc 2020 45Table 4.9 Number of male adult captured in different pheromone traps colour (window) in Vinh Phuc 2020 46Table 4.10 Number of male adult captured in different pheromone traps colour (funnel) in Vinh Phuc 2020 47Table 4.11 The density of fall armyworm on the maize field of pheromone trap height experiment in Vinh Phuc 2020 48Table 4.12 Number of male adult captured in different pheromone traps height experiment in Vinh Phuc 2020 49Table 4.13 The density of fall armyworm on the maize field of distance

pheromone trap experiment in Vinh Phuc 2020 50Table 4.14 Number of male adult captured in different pheromone traps distance experiment in Vinh Phuc 2020 50

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LIST OF FIGURE

Figure 3.1 Sample scouting pattern for maize 21

Figure 3.2 Rearing fall armyworm eggs in plastic box 22

Figure 3.3 Mating cage (A); Plastic cage for mating pairs (B) 23

Figure 3.4 Bucket funnel trap 25

Figure 3.5 Hand-made trap (funnel) (A); Hand-made trap (windown) (B); Chinese trap (C) 25

Figure 4.1 First instar's symptom 29

Figure 4.2 Second to sixth instar’s symptom 30

Figure 4.3 Egg masses of Fall armyworm 31

Figure 4.4 First instar larvae Figure 4.5 Second instar larvae 32

Figure 4.6 Third instar larvae Figure 4.7 Fourth instar larvae 32

Figure 4.8 Fifth instar larvae Figure 4.9 Sixth instar larvae 33

Figure 4.10 Pupa of fall armyworm 34

Figure 4.11 Female adult (A); Male adult (B) 34

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LIST OF DIAGRAM

Diagram 3.1 Pheromone lure types experiment 24

Diagram 3.2 Pheromone trap colour (windown) experiment 26Diagram 3.3 Pheromone trap colour (funnel) experiment 26

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ABSTRACT

Spodoptera frugiperda (J E Smith) (Lepidoptera: Noctuidae) was native to the

Americas and had invaded Vietnam This study aims to determine specific pheromone lures, trap types for fall armyworm in Vietnam and evaluate the method

of using pheromone traps for monitoring and management of FAW on maize The average life-time of female and male adults FAW were 27.43 and 25.30 days, respectively The food consuming of larvae FAW was the highest in 6th instar 770.63 mg/day/larvae In the study of pheromone types, treatments TM1, TM2, TM3 attracted more fall armyworm moths than the TM4 and TM5 and more than USA pheromone lures (TM6, TM7, TM8) Our treatment 3 captured the highest number male adult FAW in the trap 20.78 moths per trap per day while USA pheromone lure (TM7) was 13.30±1.81 moths per trap per day In the experiment

of pheromone trap types, the yellow hand-made (window) traps caught 2.40 moths per trap per day as much as commercial bucket trap 2.54 moths per trap per day The most effective height and distance of pheromone traps were 1.2m (2.13 moths/trap/day) and 40m (2.69 moths/trap/day) Moreover, our result shown that the density of FAW on maize field applied pheromone traps for 4 weeks was significant decreased to 0.50±0.22 larvae/m2 while on the maize field without pheromone traps it was increased to 3.30±0.76 larvae/m2 This result proved pheromone traps were effective in reducing FAW larvae in the maize field

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PART I: INTRODUCTION 1.1 Introduction

The fall armyworm (FAW), Spodoptera frugiperda (J E Smith, 1797)

(Lepidoptera: Noctuidae), was recognised as one of the most important noctuid moth pests of North and South America In addition, this pest had recently spread

to Africa and had been intercepted in Europe (Montezano et al., 2018)

In Ethiopia, at the 2017 cropping season, FAW infested more than 24% of the 2.9 million hectares planted to maize, with a total loss of more than 134,000 tons of crop worth almost $30 million (Beemer, 2018) In Brazil, several tonnes of insecticidal active ingredients were applied for FAW control each year, and it was estimated that in maize the annual losses could be between 19 and 100 % ( Montezano et al., 2018)

FAW was first detected in Vietnam in 2019 On August 16, 2019, Ministry

of Agriculture and Rural Development (MARD) reported that 15,000 hectares of the current maize crop has been infected by FAW in 40 provinces More than 2,000 hectares are considered to be heavily infected with over eight larvae per square meter (USDA, 2019)

A pheromone trap is a type of insect trap that uses pheromones to attract (usually) male insects Female sex pheromones are chemical secreted by (usually) a female insect to attract males for mating Sex pheromones and aggregation pheromones are the most common types of pheromones in use Currently, there are several different pheromone lures being assessed as well as a variety of trap types All of these may work, but some pheromone lures also attract a limited number of non-FAW moths, which may cause some confusion (Prasanna et al., 2018)

The S frugiperda female releases sex pheromone for attracting the

conspecific male to mate The sex pheromone component of this species was first identified as (Z)-9-tetradecenyl acetate (Z9-14:Ac) by (Sekul and Sparks, 1967)

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The attractive- ness of this compound, however, seemed insufficient The history of intensive investigations and field screening for better formulation have been briefly

summarized by Tumlinson et al (1986) Two components of S frugiperda sex

pheromone were identified as Z9-14:Ac and (Z)-7-doce- cenyl acetate (Z7-12:Ac)

in a North American (Florida) population (Tumlinson et al., 1986) In addition to these two components, a third component (E)-7-dodecenyl acetate (E7-12:Ac) was found in a Brazilian (Sãn Paulo) population (Batista-Pereira et al., 2006)

Because the situation of the fall armyworm (FAW) on maize in Vietnam recently and the ability to use pheromone traps on FAW management and prevention had become urgent On that basis, under the assignment of the Department of Entomology, Faculty of Agronomy and the guidance of Dr Tran

Thi Thu Phuong, I conduct research projects: "Research on pheromone lures and

traps for monitoring and management of the fall armyworm Spodoptera frugiperda (J E Smith) on maize in Vinh Phuc, Vietnam 2020"

1.2 Objective and Requirement

- Determining morphological and biological of fall armyworm on maize

- Determining specific pheromone lures, trap types for fall armyworm in Vinh Phuc, Vietnam

- Identification of pheromone method for FAW in Vinh Phuc, Vietnam

- Determining the evolution of the FAW density on maize in the Winter crop in 2020 in Yen Lac, Vinh Phuc

Autumn-3

PART II: LITERATURE REVIEW

2.1 Research over the World

In Europe, fall armyworm present in Germany, Netherland and Slovenia In Africa, fall armyworm was accounted for without precedent for Central Africa and West, for instance in Nigeria, Sao Tomé, Benin and Togo in 2016 (Goergen et al., 2016) In 2019, it harm the yield of 47 African nations as Nigeria, Nambia, Kenya, Ghana, Ethiopia, Congo, Egypt, Sudan, Zambia, Zimbabwe, etc (Kuate et al., 2019)

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In Asia, FAW was first recorded in India and Yemen in 2018 Be that as it may, in 2019 this species was accounted for happening in over 12 Asia and Asian nations Bangladesh, China, Korea, Japan, Lao, Malaysia, Myanmar, Nepal, Philippine, Sri Lanka, Thailand, and Vietnam

In present, FAW has been distinguished on more than 180 nations and districts everywhere throughout the world, cause million tons of yields It's present from USA to ASIA, become a significant nuisance in numerous sorts of host plants, particularly on maize plant In a brief timeframe, the fall armyworm could make a high harm the economy

2.1.3 Symptoms

The adult female lays the eggs in masses, randomly distributed within the crop During the summer, egg hatch occurs in 2-3 days The newly hatched larvae immediately start feeding on the tissues, usually beginning with the tenderest portions First instar larvae usually eat the green tissue from one side of the leaf, leaving the membranous epidermis on the other side intact Older instars begin to make holes in the leaf and the fourth to sixth instars may completely destroy small plants and strip larger ones (Cruz et al., 1999)

Seedlings are fed upon within the whorl Larger larvae can cut the base of the plant Mature plants suffer attack on reproductive structures Maize leaves are eaten and the whorl (funnel) may be a mass of holes, ragged edges and larval frass Young larvae skeletonize the leaf lamina in a typical 'window-pane' damage 'Window-paning' is the most common damage symptom at early whorl; however, this is sometimes indistinguishable from damage that is due to other stem borers Usually many young larvae will be present on the same plant, but normally one or two older larvae may be found on a single plant, as others will migrate and feed on neighbouring plants Later larval instars make larger holes, causing ragged whorl leaves, and produce sawdust-like larval droppings, while fresh feeding produces

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big lumps Badly infested fields may look as if they have been hit by a severe hailstorm Fall armyworm can also destroy silks and developing tassels, thereby limiting fertilization of the ear Maize plants may have the cobs attacked by larvae boring through the kernels Damage to cobs may lead to fungal infection and aflatoxins, and loss of grain quality At high densities, large larvae may act as armyworms and disperse in swarms, but they often remain in the locality on wild grasses, if available (CABI, 2020)

2.1.4 Damage

Larvae cause damage by consuming foliage Maize plants damaged by the larvae showed characteristic shot holes on the leaves (Sisodiya et al., 2018) Young larvae initially consume leaf tissue from one side, leaving the opposite epidermal layer intact By the second or third instar, larvae begin to make holes in leaves, and eat from the edge of the leaves inward Feeding in the whorl of corn often produces

a characteristic row of perforations in the leaves Larval densities are usually reduced to one to two per plant when larvae feed in close proximity to one another, due to cannibalistic behavior Older larvae cause extensive defoliation, often leaving only the ribs and stalks of corn plants, or a ragged, torn appearance Marenco et al (1992) studied the effects of fall armyworm injury to early vegetative growth of sweet corn in Florida They reported that the early whorl stage was least sensitive to injury, the midwhorl stage intermediate, and the late whorl stage was most sensitive to injury Further, they noted that mean densities of 0.2 to 0.8 larvae per plant during the late whorl stage could reduce yield by 5 to 20 percent (Capinera, 2020)

Larvae also will burrow into the growing point (bud, whorl, etc.), destroying the growth potential of plants, or clipping the leaves In corn, they sometimes burrow into the ear, feeding on kernels in the same manner as corn earworm, Helicoverpa zea Unlike corn earworm, which tends to feed down through the silk

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before attacking the kernels at the tip of the ear, fall armyworm will feed by burrowing through the husk on the side of the ear studied larval feeding behavior, and reported that although young (vegetative stage) leaf tissue is suitable for growth and survival, on more mature plants the leaf tissue is unsuitable, and the larvae tend to settle and feed in the ear zone, and particularly on the silk tissues However, silk is not very suitable for growth Larvae attaining the corn kernels display the fastest rate of development Also, although the closed tassel was suitable with respect to survival, it resulted in poor growth Thus, tassel tissue may

be suitable for initial feeding, perhaps until the larvae locate the silk and ears, but feeding only on tassel tissue is suboptimal (Capinera, 2020)

2.1.5 Description and Life Cycle

The life cycle is completed in about 30 days during the summer, but 60 days

in the spring and autumn, and 80 to 90 days during the winter The number of generations occurring in an area varies with the appearance of the dispersing adults The ability to diapause is not present in this species In Minnesota and New York, where fall armyworm moths do not appear until August, there may be but a single generation The number of generations is reported to be one to two in Kansas, three

in South Carolina, and four in Louisiana In coastal areas of north Florida, moths are abundant from April to December, but some are found even during the winter months (Capinera, 2020)

Egg: The egg is dome shaped; the base is flattened and the egg curves

upward to a broadly rounded point at the apex The egg measures about 0.4 mm in diameter and 0.3 mm in height The number of eggs per mass varies considerably but is often 100 to 200, and total egg production per female averages about 1500 with a maximum of over 2000 The eggs are sometimes deposited in layers, but most eggs are spread over a single layer attached to foliage The female also deposits a layer of grayish scales between the eggs and over the egg mass,

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imparting a furry or moldy appearance Duration of the egg stage is only two to three days during the summer months (Capinera, 2020)

Larvae: There usually are six instars in fall armyworm Head capsule

widths are about 0.35, 0.45, 0.75, 1.3, 2.0, and 2.6 mm, respectively, for instars 1 to

6 Larvae attain lengths of about 1.7, 3.5, 6.4, 10.0, 17.2, and 34.2 mm, respectively, during these instars Young larvae are greenish with a black head, the head turning orangish in the second instar In the second, but particularly the third instar, the dorsal surface of the body becomes brownish, and lateral white lines begin to form In the fourth to the sixth instars the head is reddish brown, mottled with white, and the brownish body bears white subdorsal and lateral lines Elevated spots occur dorsally on the body; they are usually dark in color, and bear spines The face of the mature larva is also marked with a white inverted "Y" and the epidermis of the larva is rough or granular in texture when examined closely However, this larva does not feel rough to the touch, as does corn earworm, Helicoverpa zea (Boddie), because it lacks the microspines found on the similar-appearing corn earworm In addition to the typical brownish form of the fall armyworm larva, the larva may be mostly green dorsally In the green form, the dorsal elevated spots are pale rather than dark Larvae tend to conceal themselves during the brightest time of the day Duration of the larval stage tends to be about

14 days during the summer and 30 days during cool weather Mean development time was determined to be 3.3, 1.7, 1.5, 1.5, 2.0, and 3.7 days for instars 1 to 6, respectively, when larvae were reared at 25ºC (Capinera, 2020)

Pupa: Pupation normally takes place in the soil, at a depth 2 to 8 cm The

larva constructs a loose cocoon, oval in shape and 20 to 30 mm in length, by tying together particles of soil with silk If the soil is too hard, larvae may web together leaf debris and other material to form a cocoon on the soil surface The pupa is reddish brown in color, and measures 14 to 18 mm in length and about 4.5 mm in

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width Duration of the pupal stage is about eight to nine days during the summer, but reaches 20 to 30 days during the winter in Florida The pupal stage of fall armyworm cannot withstand protracted periods of cold weather For example, Pitre and Hogg (1983) studied winter survival of the pupal stage in Florida, and found 51 percent survival in southern Florida, but only 27.5 percent survival in central Florida, and 11.6 percent survival in northern Florida (Capinera, 2020)

Adult: The moths have a wingspan of 32 to 40 mm In the male moth, the

forewing generally is shaded gray and brown, with triangular white spots at the tip and near the center of the wing The forewings of females are less distinctly marked, ranging from a uniform grayish brown to a fine mottling of gray and brown The hind wing is iridescent silver-white with a narrow dark border in both sexes Adults are nocturnal, and are most active during warm, humid evenings After a preoviposition period of three to four days, the female normally deposits most of her eggs during the first four to five days of life, but some oviposition occurs for up to three weeks Duration of adult life is estimated to average about 10 days, with a range of about seven to 21 days (Capinera, 2020)

2.1.6 Host Range

The FAW has a very wide host range, with over 80 plants recorded, but clearly prefers grasses The most frequently consumed plants are field maize and sweet maize, sorghum, Bermuda grass, and grass weeds such as crabgrass (Digitaria spp) When the larvae are very numerous they defoliate the preferred plants, acquire the typical “armyworm” habit, and disperse in large numbers, consuming nearly all vegetation in their path Many host records reflect such periods of abundance and are not truly indicative of oviposition and feeding behavior under normal conditions Field crops are frequently injured, including alfalfa, barley, Bermuda grass, buckwheat, cotton, clover, maize, oat, millet, peanut, rice, ryegrass, sorghum, sugar beet, Sudan grass, soybean, sugarcane,

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timothy, tobacco, and wheat Among vegetable crops, only sweet maize is regularly damaged, but others are attacked occasionally Other crops sometimes injured are apple, grape, orange, papaya, peach, strawberry, and a number of flowers Weeds known to serve as hosts include bent grass, Agrostis ssp.; crabgrass, Digitaria spp.; Johnsongrass, Sorghum halepense; morning glory, Ipomoea spp.; nutsedge, Cyperus spp.; pigweed, Amaranthus spp.; and sandspur, Cenchrus tribuloides (Prasanna et al., 2018)

According to research in the world of host plants for S frugiperda The literature review and surveys resulted in a total of 353 S frugiperda larval host

plant records belonging to 76 plant families, principally Poaceae (106), Asteraceae (31) and Fabaceae (31) Maize, sorghum, and wheat are the main host crops of the FAW In addition, they also cause serious harm to many other crops such as sugarcane, cotton, soybean, peanut, sunflower, onion, garlic, turnip, cruciferae, cucurbitaceae, tomato, sweet potato, apple, mango etc (Montezano et al., 2018)

2.1.7 Management

* Sampling: Moth populations can be sampled with black light traps and pheromone traps; the latter are more efficient Pheromone traps should be suspended at canopy height, preferably in corn during the whorl stage Catches are not necessarily good indicators of density, but indicate the presence of moths

in an area Once moths are detected it is advisable to search for eggs and larvae

A search of 20 plants in five locations, or 10 plants in 10 locations, is generally considered to be adequate to assess the proportion of plants infested Sampling

to determine larval density often requires large sample sizes, especially when larval densities are low or larvae are young, so it is not often used (Capinera, 2020)

* Insecticides: Insecticides are usually applied to sweet corn in the southeastern states to protect against damage by fall armyworm, sometimes as

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frequently as daily during the silking stage In Florida, fall armyworm is the most important pest of corn It is often necessary to protect both the early vegetative stages and reproductive stage of corn Because larvae feed deep in the whorl of young corn plants, a high volume of liquid insecticide may be required

to obtain adequate penetration Insecticides may be applied in the irrigation water if it is applied from overhead sprinklers Granular insecticides are also applied over the young plants because the particles fall deep into the whorl Some resistance to insecticides has been noted, with resistance varying regionally Foster (1989) reported that keeping the plants free of larvae during the vegetative period reduced the number of sprays needed during the silking period The grower practice of concentrating the sprays at the beginning of the silking period instead of spacing the sprays evenly provided little benefit (Capinera, 2020)

* Cultural techniques: The most important cultural practice, employed widely in southern states, is early planting and/or early maturing varieties Early harvest allows many corn ears to escape the higher armyworm densities that develop later in the season (Mitchell 1978) Reduced tillage seems to have little effect on fall armyworm populations (All 1988), although delayed invasion by moths of fields with extensive crop residue has been observed, thus delaying and reducing the need for chemical suppression (Capinera, 2020)

* Host plant resistance: Partial resistance is present in some sweet corn varieties, but is inadequate for complete protection (Capinera, 2020)

* Biological control: Although several pathogens have been shown experimentally to reduce the abundance of fall armyworm larvae in corn,

only Bacillus thuringiensis presently is feasible, and success depends on having

the product on the foliage when the larvae first appear Natural strains

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of Bacillus thuringiensis tend not to be very potent, and genetically modified

strains improve performance (Capinera, 2020)

2.1.8 Female sex pheromone of fall armyworm

A pheromone trap is a type of insect trap that uses pheromones to attract (usually) male insects A pheromone is a chemical secreted by (usually) a female insect to attract males for mating Pheromones can travel by air very long distances and hence are very useful for monitoring insect presence Sex pheromones and aggregation pheromones are the most common types of pheromones in use Currently there are several different pheromone lures being assessed as well as a variety of trap types All of these may work, but some pheromone lures also attract

a limited number of non-FAW moths, which may cause some confusion (Prasanna

et al., 2018)

The S frugiperda female releases sex pheromone for attracting the

conspecific male to mate The sex pheromone component of this species was first identified as (Z)-9-tetradecenyl acetate (Z9-14:Ac) by (Sekul and Sparks, 1967) The attractive- ness of this compound, however, seemed insufficient The history of intensive investigations and field screening for better formulation have been briefly

summarized by (Tumlinson et al., 1986) Two components of S frugiperda sex

pheromone were identified as Z9-14:Ac and (Z)-7-doce- cenyl acetate (Z7-12:Ac)

in a North American (Florida) population (Tumlinson et al., 1986) In addition to these two components, a third component (E)-7-dodecenyl acetate (E7-12:Ac) was found in a Brazilian (Sãn Paulo) population (Batista-Pereira et al., 2006)

Pheromones can be used in four strategies in integrated pest management programs, specifically monitoring, mass trapping, attraction annihilation, and mating disruption Trap variables, such as design, size, and color are important features, along with the attractant, in the first three strategies Ideally, traps should

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be easy to use, of standard construction, and inexpensive When a trap is constructed, characteristics such its design, size, and color in relation to the insect behavior should be considered A variety of traps have been designed for several insect pests and many of them are commercially available However, a number of biological and environmental factors can affect traps efficiency and use in insect pest management programs Trap color may influence the number of target insects, including predators, parasitoids, and pollinators Attraction of beneficial insects to trap colors needs to be addressed during trap development in order to minimize nontarget effects

Commercially available sex pheromone-baited traps have been used in a

number of countries for monitoring the fall armyworm (FAW), Spodoptera

frugiperda (J E Smith), males in corn fields For example, in the United States, S frugiperda males are frequently monitored with plastic funnel traps (e.g., Universal

moth traps, bucket traps, or uni- traps) However, funnel traps had a poor efficiency compared to Scentry Heliothis and delta traps in catching FAW males in the coastal plain of Chiapas, Mexico Scentry Heliothis trap was the most effective trap in capturing FAW males in corn and sorghum fields in Mexico Nevertheless, this kind of trap is expensive and prone to be stolen or destroyed, which may limit its use in some areas of Mexico (Malo et al., 2018)

Monitoring, surveillance, and scouting are critical activities to support a successful integrated pest management program that includes resistant varieties, biological control, and cultural control strategies Monitoring actively tracks the presence, population size, and movement of a pest and for fall armyworm, it is best achieved using pheromone-based traps that attract male moths Adult males have been monitored for over 40 years with commercial versions of female-produced sex pheromones as lures, but there are several pheromone blends and styles of traps that are available and the various combinations may provide conflicting results

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among geographic regions Field studies in the USA and Central America have shown that the chemicals needed for attraction were two acetates, (Z)-9-tetradecenyl acetate (Z9-14:Ac) and (Z)-7-dodecenyl acetate (Z7-12: Ac) (Meagher

et al., 2013) The addition of two other acetates, (Z)-11- hexadecenyl acetate 16:Ac) and (Z)-9-dodecenyl acetate (Z9-12:Ac), did not improve attraction ofmoths to traps (Meagher et al., 2013) Studies in Brazil found that the E isomer of dodecenyl acetate (E7-12:Ac) significantly increased trap capture These results indicate that there may be regional differences in the attractiveness of pheromone blends

(Z11-Differences in pheromone lure composition are also known to influence the number of non-target insects that are collected This was shown to be an important consideration for monitoring fall armyworm in North America In Florida, non-target moths rarely comprise more than 10% of the total captures, but experiments

in the northeastern USA showed that commercial lures containing three or four fall armyworm pheromone components attracted large numbers (38–48% of total captures) of the non-target species Leucania phragmatidicola Traps baited with two-component lures (Z9-14:Ac and Z7-12:Ac) had low L phragmatidicola

captures (0.5–1.4%) but also captured fewer S frugiperda Additional screening or

handling of trap samples and possible misidentification of target species decreases the efficiency and value for the monitoring system

Spodoptera frugiperda (J.E Smith) (Lepidoptera: Noctuidae) has recently

invaded Okinawa, Japan via Africa, South Asia and China Gas chromatography/mass spectrometry analyses of hexane extracts of 100 abdominal glands of Okinawan females revealed six candidate compounds for sex pheromone, (Z)-9-tetradecenyl acetate (Z9-14:Ac, ca 6 ng/female), (Z)-11-hexadecenyl acetate, (Z)-11-tetradecenyl acetate, (Z)-7-dodecenyl acetate (Z7-12:Ac), (E)-9-dodecenyl acetate, and (Z)-9-tetradecen-1-ol at the ratio of 100:10:1.3:0.90:0.13:1.8,

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respectively In Okinawa, only small numbers of males were captured with the original blend of these compounds However, much more males were attracted to a 100:3 blend of Z9-14:Ac and Z7-12:Ac that had been suggested by others to be the most effective blend in a Florida population In another test in Okinawa, even more males were captured with a 100:1 blend of these compounds than with a 100:3 blend Significant numbers of males of other moths, Mythimna loreyi (Duponchel) and Chrysodeixis eriosoma (Doubleday), were also attracted to blends of Z9-14:Ac and Z7-12:Ac when the ratio of the latter to the former compound was increased from 100:1 to 100:10 Based on these results that had the most powerful as well as

convenient sex pheromone formulation to monitor S frugiperda populations in

Okinawa was a 100:1 blend of Z9-14:Ac and Z7-12:Ac (Wakamura et al., 2020)

Trap design may also influence moth capture and can significantly affect the cost of a monitoring system Plastic bucket traps are commonly used for fall armyworm and are available from several sources Moths are contained in the enclosed bucket and are killed with the use of a fumigant (Meagher et al., 2019)

armyworm Spodoptera frugiperda (FAW) that recently entered Vietnam is in

in young corn plants On April 17, 2019, after receiving positive genetic analysis results from the Centre for Agriculture and Bioscience International in the United Kingdom, PPD officially reported the existence of FAW in Vietnam On April 24

2019, MARD issued official announcement 2827/BNN-BVTV about FAW prevention and control in Vietnam

Based on a consolidation of reported figures from local sources, Post estimates that the total FAW infected area is 35,000 hectares of corn The most infected areas are in the northwest and central highlands, which are the major corn production areas, accounting for 65 percent of total corn area On August 16, 2019, MARD reported that 15,000 hectares of the current corn crop has been infected by FAW in 40 provinces More than 2,000 hectares are considered to be heavily infected with over eight larvae per square meter (USDA, 2019)

According to Vietnam General Statistics Office, as of May 15, 2020, the total planted corn area for October 2019-May 2020, was 435 thousand hectares, down three percent compared to the same period last year Table 1, consolidated from PPD weekly pest status updates, shows corn planted and FAW infected areas during the 2019/2020 winter and spring corn seasons A downward trend in FAW infected areas happened during the cooler period from November to March Areas with over eight larvae per square meter are considered to be heavily infected Heavily infected areas went from 664 hectares in November to only 9 hectares in March However, heavily infected corn area was back up to 196 hectares by late May 2020 Although in May 2019, there were 547 hectares of heavily infected

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areas and 8,915 hectares of infected areas Plant protection and agricultural extension agencies and farmers in Vietnam have taken action to reduce the effects and limit the spread of FAW However, industry sources are projecting that FAW will continue to spread and damage the next major corn planting season in 2020 (USDA, 2020)

Table 2.1 Vietnam corn planted and FAW infected area from October 2019

Sources: MARD’s Plant Protection Department Weekly Pests Status Update

On July 25, 2019, the area of maize infected with FAW in the country was 16,467 hectares, of which 2,741 hectares were heavily infected FAW appeared and damaged maize in all 6 provinces of Regional Plant Protection Center Zone 4, with

an area of over 1,223 hectares, of which the area of maize was severely damaged

by the acacia worm was 339.4 hectares and 10 hectares were damaged loss of over 70% yield This is an alien pest that has just entered Vietnam, so there are no studies on biological characteristics, ecology and prevention measures (Vu Quang Con et al., 2020)

2.2.2 Symptoms

Following the results of Tran Thi Thu Phuong et al, (2019), there is a new pest that gives substantial harm to the maize of Gialam, Hanoi Larvae show up and eat leaves from 20 to 30 days of maize germination The first stage instar immediate devour the leaves tissues and usually consume the young part of the

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plant In stage 3, larvae damage all parts of the plant: leaf tops, baby corn, young seed, … Symptoms of pests in Hanoi, Vietnam have the same symptoms of fall armyworm which was described by Cruz et al., (1999) The pest at Hanoi, Vietnam

is similar to the fall armyworm (Spodoptera frugiperda)

2.2.3 Morphological and biological of fall armyworm

Tran Thi Thu Phuong et al., (2019) reported that fall armyworm had 4 development stages: Egg, Larvae, Pupa, Adult On the field, female adult usually lay egg at both side of the maize leaves This process is happened at night Female adults lay eggs in mass in top side of the leaf Egg mass cover by white cream fur, diameter of eggs is about 0.4-0.5 mm

Sixth instar are light green to yellow brown and dark brown Head of instars have a yellow reverse “Y” in the top, grid pattern in two head side Head diameter

of full size larvae in about 2.5-2.7 mm and length of larvae is 32 to 35 mm Pupal is shiny brown and 1.6 to 1.8 cm length Female is usually longer than male Adults are 1.3-1.5 in length and 3-3.3 in wing width The front wings are brown to dark brown, back wings are white yellow The pattern of wing is different between male and female Depend on morphological, they conclude that this pest is fall

armyworm (Spodoptera frugiperda)

The egg is placed in nest, each nest has about 150 to 300 eggs Egg is global

in shape and white or light blue, then become dark until hatch New hatched larvae are white then become light green, brown, dark brown, light black Expecially, larvae have the reverse “Y” in the head and four spot in the back Pupa is shinny brown Male adults are 10 to 15 mm in wings width It’s 11 to 17 mm with female Decorated shapes of male has more highlight than female

2.2.4 Management

As recommended by the Plant Protection Department, the fall armyworm control include cultivation methods, baits, manual and chemical methods

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Farming methods: Making soil, drying soil to kill larvae, pupae in the soil or easily destroyed by natural enemies Corn rotation - wet rice right after the corn crop to kill pupae in the soil

Method of traps and baits: Use sweet and sour baits, pheromone traps to kill adults

Manual measures: Regularly check the field to collect old stage caterpillar, remove eggs (especially in the stage of 3-6 leaves to detect eggs, break and destroy them)

Chemical measures: Currently, the Plant Protection Department recommends that farmers use chemical methods to prevent acacia fall in the early 1-3 years (corn stage 3-6 leaves), spray early morning or late afternoon The Department recommends that farmers use plant protection drugs containing the following active ingredients or microorganisms: Bacillus thuringiensis, Spinetoram, Indoxacard, Lufenuron

2.2.5 Sex pheromone application in Vietnam

The pheromone application in Vietnam is not popular And Fall armyworm is a new pest, so there is not many research about sex pheromone of this pest

In August 2019, maize Research Institute has tested pheromone trap which bought from China to control Fall armyworm in maize The result shows that commercial pheromone lures were attract male adults of fall armyworm with high density

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PART III: MATERIAL AND METHOD

3.1 Objectives and Materials

- Objective: Fall armyworm Spodoptera frugiperda

- Material:

+ Food for nurturing: Maize

+ Laboratory equipment: rackets, plastic trays, plastic pots, mesh cages, quill pens, magnifying glass, cotton, scissors, drawers, 2-liter bottle, 1.5-liter coca bottle, iron wire, curtain, scissors, pliers, electric welding pen, plastic cap, bamboo pile, soap, A4 paper, notebook

+ Pheromone trap with 4 main components: Z9-14: OAc; Z7-12: OAc; Z9-12: OAc; Z11-16: OAc

3.2 Location and Time

- Identification of pheromone method for FAW in Vinh Phuc, Vietnam

- Determining the evolution of the FAW density on maize in the Winter crop in 2020 in Yen Lac, Vinh Phuc

Autumn-20

- Identification of biological and ecological characteristics of the fall

armyworm Spodoptera frugiperda on maize

3.4 Methods

3.4.1 Field survey

- Investigation of pests on crops in the field is conducted according to QCVN 01-38: 2010 / BNNPTNT National technical regulations on methods of investigation and detection of plant pests

- Investigate pests on maize pests according to QCVN 167:2014/BNNPTNT National technical regulation on methods for investigation and detection of pests of maize

01 Periodic survey: every day in the first month and every 7 days in the next month

- Select the investigation area:

+ Based on the principle of selecting the investigated area as the field representing the investigated factors such as topography, variety, season, soil layer

+ The selected field is maize cultivation area of Vinh Phuc province

+ Selection of fields to investigate: Investigate on maize varieties popularly grown in winter-spring maize crop 2020

- Select survey points: Each element investigates 10 random distributed points on the diagonal of the investigation area The survey point must be at least 2 meters from the shore

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Figure 3.1 Sample scouting pattern for maize (Marr, 2009)

- Number of survey samples per point: 1m² / point

- Conduct investigation: Observe from far and near, then count directly the number of worms and divide each stage of development of worms on each tree in the survey point, preserve the samples in insect containers

Tracking criteria:

Density of pest (head / m2) =

Infected rate (%) =

x 100 Ratio percentage of phases (%) =

x 100 Parasite rate (%) =

x 100

3.4.2 Method of rearing insect in experiments of biological characteristic of S frugiperda

Fall armyworm S frugiperda larvae are collected on the field at Phu Dong,

Gia Lam, Hanoi in large quantities and bring to the laboratory and keep in laboratory condition on maize plant in plastic cups 45 ml until pupation Pupae are separate females and males 10 females and 10 males are mating in mating cages (20x20x20 cm) and fed with 10% honey Eggs are collected and kept in a plastic box until larvae hatching Adult mating pairs are separated and laid eggs on corn

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leaves Newly hatched eggs are used to conduct experiments of biological and ecological characteristics

Figure 3.2 Rearing fall armyworm eggs in plastic box

Egg: Egg mass collected on the same date is separated and kept in the

plastics box at 30oC to monitoring the development time of the egg The number of eggs using for one experiment is at least 120 Monitor the hatching rate and development time of the egg

Larvae: egg masses are monitored every 2 hours, 7 times per day After

hatching, first instar larvae are transferred to the individual cultural plastic box and rearing in laboratory condition at 30oC Larvae are rearing on maize plant and food

is changed every day Development time and mortality of larvae from the first instar to sixth phases are recorded The number of larvae per experiment is at least

40 individuals

Pupa: After the larva stopped eating and changed to the pre-pupae stage, S

frugiperda is transferred to the plastic box containing some moist soil or west

tissue Pupae are also kept in 30oC until becoming an adult Pupae are separated

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female and male Size and weight of pupae are calculated after at 2 days pupated Monitoring the development time of pupae and mortality of pupae

Adult: 10 females and 10 males are mating in mating cages Mating pair

female and male are collected and transferred to the plastic cage containing maize plant to lay egg mass In this experiment, pre-reproduction time, reproduction time, female and male longevity are recorded Body length and wingspan are calculated for both females and males Monitoring development time of pre-reproduction, mating, reproduction, and longevity of adult

Figure 3.3 Mating cage (A); Plastic cage for mating pairs (B)

3.4.3 Method of investigation the method applied pheromone lures and traps on the field

a Pheromone lure types

Pheromone lures will be prepared by the same method of (Meagher et al., 2019)

* Pheromone lures have 9 treatments of compositions:

+ TM1: Four component (4C) contained Z9-14:OAc, Z11-16:OAc, 12:OAc and Z9-12:OAc;

+ TM2: Three component (3C) contained Z9-14:Oac, Z11-16:OAc and 12:OAc

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+ TM3: Two component (2C1) contained Z9-14:OAc and Z7-12:OAc;

+ TM4: Two component (2C2) contained Z9-14:OAc and Z9-12:OAc; + TM5: Two component (2C3) contained Z9-14:OAc and Z11-16:OAc + TM6: Four component (4C) contained Z9-14:Ac (78.3%), Z11-16:Ac (3.6%), Z7-12:Ac (11.2%), and Z9-12:Ac (7.0%) (Meagher et al., 2019)

+ TM7: two- component lure (2C) contained Z9-14:Ac (90.5%) and 12:Ac (9.5%) (Meagher et al., 2019)

Z7-+ TM8: Three-component lure (3C) contained Z9-14:Ac (66.1%), 16:Ac (4.7%), and Z7-12: Ac (29.3%) (Meagher et al., 2019)

Z11-+ TM 9: Hecxan

Pheromone traps are hung from the field in a straight line at center of the maize field The distance between traps is 20 m, the distance from the ground to the trap is 1.5 m Observe and record the number of male moths entering the trap every day in each trap and 3 repeated Monitor the number of male moths entering the trap in 30 days

TM 7-3

TM 8-3

TM 6-3

TM 9-3

TM 1-3

TM 5-1

TM 1-1

TM 7-1

TM 9-1

TM 6-1

TM 2-2

TM 3-2

TM 1-2

TM 4-2

TM 6-2

TM 5-2

TM 9-2

TM 8-2

TM 7-2

Diagram 3.1 Pheromone lure types experiment

* Trap type: Bucket funnel trap (commercial trap)

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Figure 3.4 Bucket funnel trap

b Pheromone trap types

Three kinds of trap will be used in this study:

 Hand-made trap (funnel)

 Hand-made trap (window)

 Chinese trap

Figure 3.5 Hand-made trap (funnel) (A); Hand-made trap (window) (B);

Chinese trap (C)

m, the distance from the ground to the trap is 1.5 m Observe and record the number of male moths entering the trap every day in each trap and 3 repeated Monitor the number of male moths entering the trap in 30 days

Blue White Green Control Yellow Yellow White Green Control Blue Green Yellow

Diagram 3.2 Pheromone trap colour (windown) experiment

Green Blue Yellow Control White White Control Yellow Green Blue Yellow Green White Blue Control

Diagram 3.3 Pheromone trap colour (funnel) experiment

c Distance between traps: 20, 30, 40, 50 m

Treatment inculding three component (3C) Z9-14:OAc, Z11-16:OAc and Z7-12:OAc will be used in this experimente Pheromone traps are hung from the field in a straight line at center of the maize field The distance between traps is 20,

30, 40, 50 m , the distance from the ground to the trap is 1.5 m Observe and record the number of male moths entering the trap every day in each trap and 3 repeated Monitor the number of male moths entering the trap in 30 days

d Height of trap: 1,0; 1,2; 1,5; 1,7; 2,0 m from the ground to the trap

Treatment inculding three component (3C) Z9-14:OAc, Z11-16:OAc and Z7-12:OAc will be used in this experimente Pheromone traps are hung from the

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field in a straight line at center of the maize field The distance between traps is 20

m, the height of traps are 1,0; 1,2; 1,5; 1,7; 2,0 m from the ground to the trap Observe and record the number of male moths entering the trap every day in each trap and 3 repeated Monitor the number of male moths entering the trap in 30 days

3.4.4 Calculation methods

a Average phase time

=

Combined: : Average phase time

X i : Phase time of objective n in day i

N i : The number of objectives change phase in day i

N : Sum of the observed objectives

b Average living time

=

Combined: : Average living time

ai: Living time of objective until day i

ni: Number of objectives are still alive in day i

N: Sum of the observed objectives

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3.4.5 Data processing

Data were subjected to analysis of variance (ANOVA) using IBM SPSS Statistics 20, to test the significance of differences among different treatments tested based on F-test at P = 0.05

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PART IV: RESULTS AND DISCUSSION

4.1 Harmful symptoms of fall armyworm in Vinh Phuc, Hanoi

We observed the harmful symptoms of Fall armyworm on maize inVinh Phuc, Hanoi Maize varieties were planted during our research is CP 512 First and second instar larvae devour leaf tissue from one side, leaving the opposite epidermal layer intact

Figure 4.1 First instar's symptom

By the second or third instar, larvae begin to make holes in leaves and eat from the edge of the leaves inward Feeding in the whorl of corn often produces a characteristic row of perforations in the leaves Larval densities are usually reduced

to one to two per plant when larvae feed in close proximity to one another, due to cannibalistic behavior Older larvae cause extensive defoliation, often leaving only the ribs and stalks of corn plants, or a ragged, torn appearance