Study on biological and host preference characteristics of diamond moth plutella xylostella and cabbage butterfly pieris rapae in gialam, hanoi

CONTENT PART I: INTRODUCTION 1.1 1.2 1.2.1 1.2.2 Preface Objectives and requirements Objectives Requirements PART II: LITERATURE REVIEWS 2.1 World studies record 2.2 Vietnam studies record PART III: MATERIALS AND METHODS 3.1 Objectives and study materials 3.1.1 Objects 3.1.2 Materials 3.2 Location and conducting time 3.2.1 Location 3.2.2 Conducting time 3.3 Researching content 3.4 Researching methods 3.4.1 Method to survey density 3.4.2 Rearing method 3.4.3 Method to determine selective feed tendency 3.4.4 Experiment to evaluate the efficacy of some pesticides 3.4.5 Methods of calculation 3.4.6 Data processing methods PART IV: EXPECTED RESULTS AND SCHEDULE 4.1 Expected results 4.2 Working plan PART V REFERENCES 5.1 Vietnamese references 5.2 World References PART I: INTRODUCTION 1.1 Preface Vegetables are indispensable food in the daily living needs of each family It contains a relatively large amount of carbohydrates, vitamins, protein, sugar, aromatic substances, mineral compounds and organic acids provide body Today, the living needs of people rise, the use of food species to ensure the quality, safety and health is also very important Therefore vegetables are used daily in large quantities Average daily body needs from 150-250g vegetables, with those everyday needs at least 2,000 kcal maintaining healthy weight So the issue of quality control and food safety issues always becomes the top concern of consumers In economic term, the vegetable crops are high economic efficiency According to FAO (2010), Vietnam has geographic location spanning a lot of latitudes, tropical monsoon climate and there are some special microclimates as: Da Lat, Sa Pa, Tam Dao , with favorable natural conditions for the production of vegetables There are more than 120 native vegetable plants cultivated including tropical, subtropical, temperate and furthermore the off-season vegetables are being produced to meet consumer demand and exporting sector Vegetable production tends increasingly expanding in area and production increased consensus Period 1986 – 1990, our country exports totaled 5.15 million In 1997, exports of Vietnam vegetables are reached 140 million, up 170% compared to 1986 and accounted for 1.6 of the total exports of the country However, the winter and winter-spring crops in the vegetable growing areas in the Northern part of Vietnam of increasing concern about the possibility of pest and disease control by farmers and local governments According to statistics in recent years, pests component on vegetable develop richness and diversity with the worms often appear in fields such as larva of diamond moth, larva of cabbage butterfly, armyworm… Today, controlling diamond moth and cabbage butterfly is difficult They attack vegetable crops over large areas and time spans from seedling stage until harvest, reduce productivity and directly affects the quality of vegetables In order to improve the effectiveness of prevention and minimize the damage caused by diamond moth and cabbage butterfly, we conduct the research: “Study on biological and host preference characteristics of diamond moth Plutella xylostella and cabbage butterfly Pieris rapae in Gialam, Hanoi” The perspective result could help farmer improve effectiveness IPM on both two cabbage pests and ensuring food safety 1.2 Objectives and requirements 1.2.1 Objectives This study aims to: - Evaluating biological characteristics of diamond moth and cabbage butterfly under different diet condition - Surveying the emergence of diamond moth and cabbage butterfly and capture their density changing and the rate of damage in the ecological conditions, after, propose appropriate solution for management and control them to achieve economic efficiency 1.2.2 Requirements  Surveying the appearance time and abundant of insect pests on Brassica cultivar fields in Gialam district  Determining morphological and biological characteristics of diamond moth and cabbage butterfly under different diet conditions  Evaluating host plant preference of diamond moth and cabbage butterfly in Y-tube olfactometer  Evaluating the efficacy of some pesticides for controlling diamond moth and cabbage butterfly PART II: LITERATURE REVIEWS 2.1 World studies record The diamond moth Plutella xylostella (Linnaeus 1758) Scientific classification of diamond moth: Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Plutellidae Genus: Plutella Species: Plutella xylostella The diamond moth may have its origin in Europe (Hardy, 1938) but on the basis of the large complex and sexual forms of its parasitoids and host plants found in South Africa, Kfir (1998) speculated that it originated in South Africa and then dispersed to Europe Using similar arguments, Liu et al (2000) is of the view that diamond moth originated in East Asia North American populations of diamond moth are most probably of European origin (Hardy, 1983).Widespread distribution of Plutella xylostellahas been observed in British Columbia (R Sarfraz, 2014, personal observation, University of British Columbia, Vancouver, BC, Canada) Diamond moth Plutella xylostella is holometabolous insect Their life cycle included phase: egg, larva, pupa and adult Eggs are 0.44 x 0.26 mm, oval and flattened, and yellow or pale green They are deposited singly or in small groups of 2-10 eggs on foliage surfaces (Hardy, 1938; Talekar et al., 1994) or on other plant parts (Sarfraz et al., 2005) A fully-grown larva is 10 mm long The larva has five pairs of prolegs; a pair of prolegs protrudes from the posterior end forming a distinctive 'V' shape Moriuti (1986) gives details of other morphological characters such as spiracles, legs, mouthparts and chaetotaxy The larva, when disturbed, curls and wriggles backward violently and may drop off the plant, where it can hang suspended on a silken thread (Sarfraz et al., 2009) The sex of the moth can be visually distinguished from the third-instar larva onwards In males the 5th segment is distinctly yellow, such coloration is not found in the female larva (Liu and Tabashnik, 1997) Pupa is 5-6 mm, about four times as long as the width It is covered with a white, loose, silken cocoon Sometime pupation may take place without a silken cocoon (e.g when larvae are fed on an unusual food plant) The adult is greyish brown with a 9-mm-long body and a wingspan of about 1215 mm (Anonymous, 1983; Reid and Cuthbert, 1971) Moriuti (1986) gives details of wing venation and genitalia The moths are weak fliers and can disperse, on average, only 13-35 m within a crop field (Mo JianHua et al., 2003) They are readily carried by the wind and can travel long distances, at 400-500 km per night (Chapman et al., 2002) Due to the different in geographical and environmental conditions among countries, life cycle of Plutella xylostella changes Lee et al (1996) reported in his publication that in Hong Kong lifecycle of Plutella xylostella around 22-27 days; while in Canada they lasted from 14-21 days (Harcourt 1963) Diamond moth attacks only plants in the family Cruciferae Virtually all cruciferous vegetable crops are eaten, including broccoli, Brussels sprouts, cabbage, cauliflower, kohlrabi, mustard, radish Several cruciferous weeds are important hosts, especially early in the season before cultivated crops are available Plant damage is caused by larval feeding Although the larvae are very small, they can be quite numerous, resulting in complete removal of foliar tissue except for the leaf veins This is particularly damaging to seedlings, and may disrupt head formation in cabbage, broccoli, and cauliflower Diamond moth Plutella xylostellacan be controlled by any ways Populations are usually monitored by making counts of larvae, or by the level of damage In Texas, average population densities of up to 0.3 larvae per plant are considered to be below the treatment level In Florida and Georgia, treatment is recommended only when damage equals or exceeds one hole per plant Pheromone traps can be used to monitor adult populations, and may predict larval populations 11 to 21 days later However, because of variation among locations, each crop field requires independent Protection of crucifer crops from damage often requires application of insecticide to plant foliage, sometimes as frequently as twice per week However, resistance to insecticides is widespread, and includes most classes of insecticides including some Bacillus thuringiensis products Rotation of insecticide classes is recommended, and the use of B thuringiensis is considered especially important because it favors survival of parasitoids Rainfall has been identified as a major mortality factor for young larvae, so it is not surprising that crucifer crops with overhead sprinkle irrigation tend to have fewer diamond moth larvae than drip or furrow-irrigated crops Best results were obtained with daily evening applications.Crop diversity can influence abundance of diamond moth Larvae generally are fewer in number, and more heavily parasitized, when crucifer crops are interplanted with another crop or when weeds are present.Crucifer transplants are often shipped long distances prior to planting and diamondback moth may be included with the transplants The cabbage butterfly Pieris rapae (Linnaeus 1758) Scientific classification of cabbage butterfly: Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Pieridae Genus: Pieris Species: Pieris rapae Pieris rapae was first described by Linnaeus in 1758 as Papilio rapae, but subsequently placed in the genus Pieris by Schrank Pieris rapae is the preferred and most often used name Pieris rapae is essentially a northern temperate species with its origins in Europe It was accidentally introduced into China (Yin et al., 1989), North America (in 1860), Australia (in 1937) and New Zealand (in 1930) The complete life cycle of this insect requires three to six weeks, depending on weather The number of generations reported annually is two to three in Canada, three in the New England states, three to five in California, and six to eight in the south Imported cabbageworm can be found throughout the year in Florida The egg of Pieris rapae is pale yellow and about mm long It is twice as high as it is wide, giving it a spindle shaped appearance It has a narrow base and blunt apex and usually shows 14 pronounced vertical ribs and numerous faint horizontal lines It is attached endwise to the leaf surface The head and body of the first-instar larva are pale yellow with fine transparent hairs arising from small white spots The mature larva is about cm long, its head and body are velvety green with short hairs There is a faint yellow middorsal line and numerous black, and occasional white, minute raised spots from which arise short translucent hairs Segments have one or two yellow lateral spots The larva has five pairs of prolegs The pupa is 18-20 mm long and has a pointed anterior spine The thorax and abdomen have a dorsal ridge with paired pointed dorsolateral ridges Pieris rapae is a white, diurnally active butterfly with a wingspan of 4-6 cm The wings are white with a black area near the tip of each forewing and a small black spot on the front edge of the wing Adult Pieris rapae live for 5-20 days The females usually begin laying eggs within a day or so of eclosion and lay 400-1000 eggs during their lifetime (Suzuki, 1978) Fecundity is influenced by mating frequency (Watanabe and Ando, 1993, 1994) and is greatest when immature stages develop under warm conditions (Jones et al., 1982) The eggs contain an oviposition-deterring pheromone (Schoonhoven et al., 1990) which facilitates the optimal dispersal of the eggs The adults disperse a long way and female flight paths may be up to 700 m/day (Jones et al., 1980), ensuring efficient location of the host plants which are generally common (Fahrig and Paloheimo, 1987) According to John L Capinera (2000), Pieris rapae appeared on the cruciferous vegetables such as cabbage, kohlrabi, cauliflower Larvae of Pieris rapae damage cruciferous crops by chewing leaves, hearts and curds, if not kill them, it will affect seriously to plant growth Classical control was carried out in a number of countries: Australia: partial control achieved (Wilson, 1960) New Zealand: substantial control achieved (Cameron et al., 1989, 1995) Canada: parasitoids established (Corrigan, 1983) USA: substantial control according to Clausen (1978) In recent years, good control has been achieved using managed spray or IPM programmes (Leibee et al., 1984; Theunissen, 1984; Stewart and Sears, 1988; Ferguson and Barratt, 1993) These generally combine close monitoring of pest and natural enemy populations with judicious applications of selective pesticides (Jackson and Hartley, 1982; Endersby et al., 1992; Forster and Hommes, 1992; Dornan et al., 1994) New plantings should be as far as possible from those of the previous season At the end of the season crops should be harvested without delay and plant residues should be ploughed under or destroyed Intercropping and trap crops have had limited success as methods of controlling Pieris rapae (Kenny and Chapman, 1988; Luther et al., 1996; Wiech, 1996) Both strategies are likely to have some value in IPM systems based on pesticides or natural enemies Paper caps early in the season, and row covers later, are effective in preventing oviposition by imported cabbageworm butterflies 2.2 Vietnamese studies record Diamond moth Plutella xylostella and cabbage butterfly Pieris rapae were distributed in all regions of vegetable production from the north to the south of Vietnam However, the quantity and duration of each species have incurred significantly different between the North and South According to Nguyen Cong Thuat (1985) on brassica, diamond moth Plutella xylostella and cabbage butterfly Pieris rapae are the major pest Mai Van Quyen and collaborators (1995) reported in the area of Ho Chi Minh City and southern provinces that there are serious pests damaging, in which diamond moth Plutella xylostella and cabbage butterfly Pieris rapae appear with large quantity The result of survey of the actual use of plant drugs on some agricultural plains of the Red River have identified diamond moth Plutella xylostella and cabbage butterfly Pieris rapae are major pests and appear high frequency Studies of Le Van Trinh, Vu Thi Su and Nguyen Thi Nguyen about insect pests on cruciferous vegetable in Red river Delta from 1995 to 1999 showed that development time of diamond moth Plutella xylostella’s egg is from 1.9 to 4.8 days, larval phase could be divided into instars: st instars last from 1.0 to 4.9 days, 2nd instars from 1.1 to 3.2 days, 3rd instars from 1.1 to 3.6 and 4th instars from 1.7 to 7.0 days After, pupal phase varies from 3.0 to 8.0 days The average longevity of female and male is and days, respectively The life cycle of Plutella xylostella varies about from 11.5 to 33.1 days and their life cycle depended on the daily average temperature from 17.2 to 30.1 oC Also in this study, the development time of egg phase of and cabbage butterfly Pieris rapae varies from 2.2 to 3.5 days 1st instars last from 1.2 to 2.7 days; 2nd instars: 1.72.3 days; 3rd instars: 1.8-2.3 days; 4th instars: 2.2-2.9 days and 5th instar: 2.3-3.8 days Pupal stage last from 5.0 to 10.8 days Adult males and females live about days, and females deposit eggs for about days The life cycle of Pieris rapae varies from 19.3 to 30.0 days Diamond moth Plutella xylostella and cabbage butterfly Pieris rapae is two major pests damage cruciferous vegetable Each year from 1995 to 1999 has 17 times of the highest density of diamond moth Plutella xylostella and 15 times of the highest density of cabbage butterfly Pieris rapae The processing development of diamond moth Plutella xylostella and cabbage butterfly Pieris rapae depended on the processing development of vegetable crops Farmers based on the day grown vegetable to control them In Red river Delta in 1996, NPV, natural enemy of diamond moth Plutella xylostella and cabbage butterfly Pieris rapae, killed 19-24.7% of their populations Wasps in the family Braconidae also contributed to increasing density of diamond moth Plutella xylostella and cabbage butterfly Pieris rapae populations PART III: MATERIALS AND METHODS 3.1 Objects and study materials 3.1.1 Objects Diamond moth Plutella xylostella and cabbage butterfly Pieris rapae 3.1.2 Materials - Brassica vegetables: cabbage, kohlrabi, cauliflower, Rorippa indica (wild mustard)… - Collecting tools: Rackets, microscopes, tweezers, scissors, sample containers, questionnaires, notebook, pens… - Laboratory equipments: Climate cabinet, microscopes, rearing cages, hand sprayer, commercial pesticides… 3.2 Location and conducting time 3.2.1 Location - Brassica cultivar fields in Gialam District, Hanoi city - Entomology Laboratory- Dept of Entomology, Faculty of Agronomy, VNUA 3.2.2 Conducting time From July 1st2015 to Dec 31st 2015 3.3 Researching content - Surveying the appearance time and abundant of insect pests on Brassica cultivar fields in Gialam district - Determining morphological and biological characteristics of diamond moth and cabbage butterfly under different diet conditions - Evaluating host plant preference of diamond moth and cabbage butterfly in Y-tube olfactometer - Evaluating the efficacy of some pesticides for controlling diamond moth and cabbage butterfly 3.4 Researching methods 3.4.1 Methods to survey density of diamond moth Plutella xylostella and cabbage butterfly Pieris rapae - Surveying follow to National technical regulation on Surveillance method of plant pests issued along with decision QCVN 01-38:2010/BNNPTNT - To estimate density of different pests in brassica investigation field, direct counts of adult insects, larvae and adults of them will be carried time/week on Monday and Tuesday during brassica season to determine number of them on field Direct counts in the crop will be made by visually determining the number pests in 10 oblique points (1m2) on each field Data reported as the number of each pest per plant or each pest per 1m2 in each section 3.4.2 Rearing methods of diamond moth Plutella xylostella and cabbage butterfly Pieris rapae Seedling preparation Seedlings of cabbage or radish (mustard as well as Rorippa indica) are used as rearing materials To prepare the seedlings, seeds are soaked in water for to 24 h, and then treated with disinfectants for 30 Disinfected seeds are transferred into a small plastic vessel with a perforated lid on top and a piece of paper at the bottom on which the seeds are sown Each vessel is filled with water The seeds begin to sprout after one day, and are ready to feed larvae on their cotyledons in three days Rearing Procedure First larvae for the rearing were collected in the fields of Gialam district The larvae were set in plastic boxes in the rearing chamber and fed with leaves from cabbage or radish until pupation The emerged adults were placed in mating chambers, for mating and egg lying Mass rearing These mating chambers were made of big plastic containers with the upper-parts removed and covered with fine mesh cloth held in place by a rubber band The adults were fed with 5-10 % honey solution in a cotton wick, put on a plastic sauce container The females could lay their eggs either underneath the cloth or at the sidewalls of the water container One to three pairs were set in one chamber Dead adults were immediately removed to avoid moulding of the corpses Eggs were collected or left on the spot where the females had laid them In the latter case, the hatched first instars were transferred to potted plant or in boxes with plant material using a fine brush The food was exchanged every two to three days When the larvae were brought to a whole plant, it was necessary to transfer them again to a box with food after 4-8 days on a plant The larvae were fed with leaves from cabbage, mustard and radish as well as Rorippa indica 3.4.3 Method to determine selective feed tendency of diamond moth and cabbage butterfly in Y-tube olfactometer Repeated the experiment conducted on 30 larvae each Plutella xylostella and Pieris rapae for each experimental Brassica varieties in Y-tube olfactometer with one branch containing mustard plants affected by: - Artificial damage by using a needle to leaf - Artificial damage by crushed leaves - Natural foliar damage by Plutella xylostella and Pieris rapae and the other branch contains control undamaged leaves the same variety 10 Clean air is blown into the chamber to maintain the flow of glass with 800ml / minute in lighting conditions and room temperature Use a stopwatch to count the speed and direction of movement of larvae for improved varieties widely planted in the field 3.4.4 Experiment to evaluate the efficacy of some pesticides for controlling diamond moth and cabbage butterfly Arrange experiments corresponding to formula of three pesticides: - Experiment 1: Pesticide - Experiment 2: Pesticide - Experiment 3: Pesticide - Experiment 4: control sprayed with water Replicate one more times with 10 larvae in one Petri dish with leaves exposed pesticide + Leaves could be dipped in pesticide solution + Use spray tower to spray pesticide on foliar surface with recommended concentration Observe and record numbers of insects are still alive after expose to pesticide 24 hours and 48 hours 3.4.5 Methods of calculation -Density (individuals/plant) = -Percentage damage (%) x 100 -The appearance frequency (%) = x100 In which: ++++: Very common (appearance frequency >50%) +++ : Common (appearance frequency 25-50%) ++ : Less common (appearance frequency 5-25%) + : very less common (appearance frequency