Studies of Occurrence of Pod Borer Heliothis Viriplaca in Relation to the Phenology of Chickpea in Rain-Fed Chickpea Fields in Kermanshah Region of Iran

Full Length Research Paper

Studies of occurrence of pod borer Heliothis viriplaca in relation to the phenology of chickpea in rain-fed chickpea fields in Kermanshah region of Iran

Morteza Kahrarian

Kermanshah Branch, Islamic Azad University, Kermanshah, Iran. E-mail: [email protected]. Tel: 98-831- 8247901. Fax: 98-831-8237775.

Accepted 30 September, 2011

In order to determine the seasonal occurrence of Heliothis viriplaca as well as the best timing of sprays in relation to the phenology of chickpea, light-traps and monitoring methods were applied. All experiments were conducted in two research stations (Mahidasht and Sararood) in 2003 and 2004. The results of adult moths caught by light-traps showed that this pest has only one generation per year and the maximum adult population density appears in the field from end May until early June. The results show that the population density of H. viriplaca was 95% while population density of Helicoverpa armigera and Helicoverpa peltigera were 2 and 3%, respectively. A comparison of the flight peak, the peak of pod borer oviposition, peak of activity of larvae populations and the phenology of plant showed that a period of 13 to 15 days after the flight peak of H. viriplaca was most appropriate for chemical control. This time period coincided with 50% of plant flowering. The field experiments showed that fully grown larvae of H. viriplaca were parasitized by the Habrobracon hebetor , but in this time, most of the larvae had bored the pod of chickpea so this parasitic wasp is likely not to be an adequate agent for pest control.

Key words: Pod borer, Heliothis viriplaca , phenology, light trap.

INTRODUCTION

Chickpea Cicer arietinum L. is the third most important of leaves and reproductive organs (flower and blossoms), grain legume crop in the world (Romeis et al., 2004), and while, late instar larvae (usually III, IV and V instars) it is important as food, feed and fodder (Singh, 1997). In bored pods and feed on the seeds. Iran, the climate of this plant producing area is mainly In the old sources of Iran, this pest is mostly mistaken cool and cold semi-arid with a high variability in rainfall with similar species such as Helicoverpa armigera . (Soltani et al., 1999). Although relative to other pulses, Behdad (1989) expressed two to three generation for this chickpea has remarkably few insect pest problems pest, but Jozeian (2002), and Mahjob and kaviani (2002), (Williams et al., 1991), however some of this pest such as suggested one generation in Ilam and kermanshah Heliothis larvae do cause extensive damage and control provinces, respectively. Other experiment showed that method need to be developed. The legume pod borer H.viriplaca has only one generation in Syria, Turkey Heliothis viriplaca Huf. is the major insect pest of (Saxena et al., 1996) and Israel (Kravchenco et al., chickpeas in Iran. In some years, the damage of this pest 2005). Knowing the exact time of using pesticides is one is so severe that chickpea yield was reduced to about of the most important conditions for use of pesticides. 90% (Kahrarian, 2009).This pest is distributed in Middle Unfortunately, in many cases, spraying time is East, Central England through Europe to Altai Mountains inappropriate. A large number of entomologists studied to Morocco and Algeria (Kravchenco et al., 2005), and in the population fluctuations of H. armigera on ckickpea the eastern Mediterranean countries such as Turkey and (Deka et al., 1989; Prasad et al., 1989; Patnaik and Syria (Weigand, 1996). Early instar larvae (usually I and Senapati, 1996; Khurana, 1997; Patel and Koshiya, 1997, II instar) of this pest initially feed on parenchymal tissue 1999) but research on population fluctuation of H.

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viriplaca is limited. The aim of this study was to determine moderate (instar III and IV) and large (V instar larvae and prepupa). the seasonal occurrence of this pest as well as the best timing of sprays in relation to the phenology of chickpea. Population density in other species of pod borer In addition, number of generation of this pest in western Iran using photo trap and monitoring methods was also In addition to H. viriplaca , other species that had been caught by recorded. light traps were identified each day. With this method, the population of these species was identified.

MATERIALS AND METHODS Possibility of natural enemies

Seasonal occurrence of H. viriplaca and host plant phenology To record the population of emerging parasitoid adults, larvae were Recorded different stages of plant growth collected from insecticide free fields and kept under laboratory conditions (25±2°C and relatively humidity 70±5%). In order to get more accurate information from chickpea phenology and compare it with the various developmental stages of pest, peas were planted in an area of 2000 m3 of lands, in two research RESULTS stations; Mahidasht and Sararood belonged to Pest and Diseases Research Center of Kermanshah, Iran (34°N, 46°79 E; 1352 m and The results of adult moth catches with light traps in 34°23 N, 47°8 E; 1351 m elevation, respectively). After growing peas, different growth stages were studied in these two fields. The Mahidasht research station showed that the adult first following information were noted; 1) emergency stage; 2) flowering appeared in late April 2003. The peak incidence was stage; 3) 50% of flowering stage; 4) beginning of pod formation; 5) recorded during May 15 to 22. Later, the population 50% of pod formation stage. reduced and was nil during the end of May until 26 June Randomly assigned, 50 pea plants were chosen, at each visit. (Figure 1). Results obtained from adult moths caught by Number of flowers to bloom, were counted. This method continued light traps in two years in the research station Sararood, until the 50% flower became to blossom. Also, 50 pea plants were selected from each visit after pod formation and the number of pods showed that the first adult moths were caught in late than the flowers was counted. This method continued until 50% of April. Maximum adult population density appeared in the the flowers became pod. field from May 20 to 27, and May 10 to 17, in 2003 and 2004, respectively (Figure 1) and finally reached zero. Both sexes were caught by the light trap. On the other Determination of the seasonal occurrence of H.viriplaca hand, females mating were attracted to the light traps.

To study the population fluctuations of adult moths, and providing accurate information from the time of emergence, and adult moths flying peak, light traps with fluorescent lamps were placed in two Counting egg density and egg distribution research stations; Sararood and Mahidasht. Based on the approximate date of emergence of adult moths, light traps were Results of egg counts are shown in Figure 2. Results placed in both areas, almost two weeks before appearing on adult insects. Adult moths caught by light traps, were counted every day, show that females of H. viriplaca , laid from early May and were noted in separate forms. In addition, the containers (average, 14 days after adult flight peak) and the average containing pesticide were replaced every two weeks. Due to laying ended in early June. Usually, the eggs were placed numerous problems, in the second year, light trap were installed, in a batch of four to ten, in the back of the leaves. Most of only at Sararood Research Station, and data collection was done these eggs were trailed in the third top of chickpea. only in this area.

Determination of the egg density and distribution Larvae counting

In order to obtain distribution of eggs and laying rate of this pest, Results from counting larvae, showed that the first small pea fields were monitored, twice weekly. 100 plants were selected larvae of these pests, were seen from early May (May 5), randomly, from each field and the number of eggs was counted. and after this, the population of small larvae, increased, Each selected plant was divided into three parts, high, middle and end of pea plants. In each visit, front and under surface of 50% so in late May (25 until 30 May 2004), it reached the leaves per plant were counted and the number of eggs was notes, if highest density. At this time, medium and large larvae egg was seen. were found in low densities (Figure 3).

Larvae counting Record different growth stages of chickpea

After chickpea emergence, field visits were made once every three days. As and when H. viriplaca larvae appeared, fields were visited Results related to the recorded different growth stages of once every week. For this purpose, 100 plants from each field were pea plants are expressed in Tables 1, 2 and 3. The selected randomly, and larvae in each plant were counted. Larvae results show that, in the first year, at Mahidasht research were grouped by size into three types; small (instar I and II), station, 50% of flower formation in pea plants, was at

2192 Afr. J. Biotechnol.

4 3 2 y = 0.0262x - 0.6585x + 5.1626x - 12.88x + 9.3636 2 R = 0.6959 20

moths moths 5 Number of adult adult of Number 0 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th -5

1st= 2003.4.17 Time (weeks) a y = 0.0228x5 - 0.5107x4 + 3.7544x3 - 10.774x2 + 15.665x - 6.8 R2 = 0.7223 40 35 30 25 20

moths moths 15 10 Number of adult adult of Number 5 0 -5 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 1st=2003.4.22 Time (weeks) b

Figure 1. Illustration of adult moths of H. viriplaca caught by light trap. a) Mahidasht research station in 2003; b) Sararood research station in 2003; c) Sararood research station in 2004.

y = -0.0565x5 + 1.5398x4 - 15.032x3 + 62.111x2 - 97.261x + 47.933 R2 = 0.6946 45 40 35 30 25 20

moths 15 10 Number of adult 5 0 -5 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 1st=2004.4.26 Time (weeks) c

Figure 1. Illustration of adult moths of H. viriplaca caught by light trap. a) Mahidasht research station in 2003; b) Sararood research station in 2003; c) Sararood research station in 2004.

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30 3 2 y = -0.0589x - 0.2904x + 7.2685x - 1.7778 25 2 R = 0.7487 20 15 10

batch batch 5

Number of eggs of Number 0 -5 2 0 0 4 . 5 . 3 2 0 0 4 . 5 . 8 2004.5.15 2004.5.21 2004.5.24 2004.5.29 2 0 0 4 . 6 . 4 2 0 0 4 . 6 . 9 2004.6.15

Time

Figure 2. Counted eggs batch of Heliothis viriplaca in Sararood research station in 2004.

220 200 180 160 140 120 100

larvae 80

Number of of Number 60 40 20 0 2 0 0 4 . 5 . 5 2 0 0 4 . 5 . 8 2 0 0 4 . 5 . 1 5 2 0 0 4 . 5 . 2 2 2 0 0 4 . 5 . 3 1 2 0 0 4 . 6 . 6 2 0 0 4 . 6 . 1 3 2 0 0 4 . 6 . 2 0 2 0 0 4 . 6 . 2 7 2 0 0 4 . 7 . 4 2 0 0 4 . 7 . 1 1

Time

Small larvaed Moderat larvae Full grow larvae

Figure 3. Illustration of counted larvae of H. viriplaca in Sararood research station in 2004.

early June (June 4) and 50% of pea pods formation, was H.viriplaca ,. In Srarood research station, 50% flowering at mid-June (June 11) while in Sararood Research stage during the two years (2003 and 2004), were Station, 50% of flower formation, in 2003 and 2004 were concurrent with 15 and 14 days after flight peak of this on June 11, and May 31, respectively, and 50% of pods pest, respectively. The results show that, 14 to15 days formation in 2003 and 2004, were on June 15, and June after flight peak of H. viriplaca coincided with 50% of 5, respectively (Figure 4). chickpea flowering (Figure 5).

Comparison of flight peak of H. viriplaca with Comparison of the peak population density of small different stage of growth in chickpea larvae of H. viriplaca with different stage of growth in chickpea Comparison of flight peak of H.viriplaca , with different stages of growth in pea plants showed that, in Mahydsht Results related to recorded peak population density of Research Station, 50% of flower formation in pea plants small larvae (instar I and II) with different stage of growth was concurrent with 13 days after flight peak of in chickpea show that peak population density of small

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Table 1. Different growth stages of chickpea in Mahidasht research station in 2003.

Stage growth of chickpea Date Planting 2003.3.21 Emergency stage 2003.4.6 Early of flowering 2003.5.25 50% 0f flowering 2003.6.4 Early of podding 2003.6.4 50% 0f podding 2003.6.11

Table 2. Different growth stage of chickpea in Sararood research station in 2003 at 2003 .

Stage growth of chickpea Date Planting 2003.3.20 Emergency stage 2003.4.5 Early of flowering 2003.5.25 50% 0f flowering 2003.6.11 Early of podding 2003.6.10 50% 0f podding 2003.6.15

Table 3. Different growth stage of chickpea in Sararood research station in 2004.

Stage growth of chickpea Date

Planting 2004.3.16

Emergency stage 2004.3.29 Early of flowering 2004.5.21 50% 0f flowering 2004.5.31 Early of podding 2004.5.30 50% 0f podding 2004.6.5

larvae (instar I and II) was simultaneous with 50% of However, in the research station Sararood, during two flowering in pea plants (Figure 6). consecutive years, the results show that there were 15 and 14 days interval between the flight peak of H.viriplaca , and 50% of flowering in pea plants, Determination of the best time of chemical control respectively. On the other hand, the results of larvae counted, showed that about 14 days after adult flight According to the results obtained from the light trap peak of H.viriplaca is the peak population density of small placed in Mahydsht research station, and records from larvae (instar I and II). Considering that the peak different growth stages of chickpea in this region, it was population density of small larvae, is the best time for the found that there was 13 days gap between the flight chemical control with this pest, so it can be stated that peak of H.viriplaca , and 50% of flowering in pea plants. approximately 14 days after peak flight, is the best time

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100 2 90 y = 9.2857x - 30.714x + 22 2 80 R = 0.9969 70 50% of flowering 60 50 40

of flowering 30 20 Percent of flowering of Percent 10

ercent 0 P -10 1st 5th 7th+1day 9th+3day 11th Time after emergency (weeks) a

100 2 y = 9.2857x - 30.714x + 22 90 R2 = 0.9969 80 70 60 50

of flowering 40 30 20 Percent of flowering of Percent 10 ercent

P 0 -10 1st 5th 7th+1day 9th+4 11th

Time after emergency (weeks) b

Figure 4. Different growth stage in chickpea. a) Mahidasht research station in 2003; b) Sararood research station in 2003; c) Sararood research station in 2004.

for the chemical control against larvae H.viriplaca , and relationally low population density and were included in 2 this time is simultaneous with 50% of flowering in pea to 3% of the total population of pod borer moths taken by plants (Figure 7). light traps, respectively.

Population density in other species of pod borer Results from natural enemies

Study of other species pod borer showed that in addition Results from larva sampled from insecticide free fields, to H. viriplaca , there were also species (H.armigera and showed that some of the larvae of this pest were H. peltigera ) at both regional Mahydsht and Sararood. severely, parasited by parasitc wasp Habrobracon But both H.armigera and H. peltigera were found with a hebetor (Braconidae) . Results reveal that fully grown

2196 Afr. J. Biotechnol.

100 50

90 45 80 40 70 35 60 50% flowering 30 50 25 40 20 of flowering Peak of flight 30 15 of adult moth 20 10 Percent of flowering flowering of Percent

10 5moths adult of Number

ercent 0 0 2 0 0 3 . 4 . 1 7 2 0 0 3 . 4 . 2 4 2 0 0 3 . 5 . 1 2 0 0 3 . 5 . 8 2 0 0 3 . 5 . 1 5 2 0 0 . 5 . 2 2 2 0 0 3 . 5 . 2 5 2 0 0 3 . 5 . 2 9 2 0 0 3 . 6 . 4 2 0 0 3 . 6 . 5 2 0 0 3 . 6 . 1 2 2 0 0 3 . 6 . 1 9 2 0 0 3 . 6 . 2 5 umber P N

ِ ◌ Date of sampling percent 0f flowering Number of adult moths a

100 100 90 90 80 80 70 70 60 60 50 50

of adultmoth 40 40

30 30 of flowering 20 20 Percent of flowering of Percent Number of adult moths moths adult of Number 10 10 umber 0 0 N 2 0 0 3 . 4 . 2 2 2 0 0 3 . 4 . 2 9 2 0 0 3 . 5 . 6 2 0 0 3 . 5 . 1 3 2 0 0 3 . 5 . 2 0 2 0 0 3 . 5 . 2 5 2 0 0 3 . 5 . 2 7 2 0 0 3 . 6 . 3 2 0 0 3 . 6 . 1 0 2 0 0 3 . 6 . 1 1 2 0 0 3 . 6 . 1 7 2 0 0 3 . 6 . 2 4 ercent P

ِ ◌ Date of sampling percent 0f flowering Number of adult moths b 100 100 90 90 50% flowering 80 Peak of flight 80 70 70 60 60 50 50

of adult moth 40 40 of flowering 30 30 20 20 Percent of flowering of Percent Number of adult moths moths adult of Number umber

10 10 ercent N 0 0 P 2004.4.26 2004.5.3 2004.5.10 2004.5.17 2004.5.22 2004.5.24 2004.5.31 2004.6.7 2004.6.14 2004.6.21 2004.6.27 2004.6.28

ِ ◌ Date of sampling

percent 0f flowering Number of adult moths

Figure 5. Comparison of peak of flight of H. viriplaca with 50% flowering of chickpea. a) Mahidasht research station in 2003; b) Sararood research station in 2003; c Sararood research station in 2004.

larvae of H. viriplaca were parasitized by the parasitic This peak usually occurs in late June to July and then, wasp H. hebetor inside the pods by H. hebetor. The first the populations of adult moth taken by the light trap were parasitic larvae were observed from mid-January and low, so its reached zero around late September. These thereafter, the parasite rate was greatly increased over results indicate that the considered pests, has only one time, so that in early July, many of the larvae were generation in Kermanshah province and western Iran. approximately parasites of by wasp (Table 4). Kahrarian et al. (2010) showed that under laboratory conditions, this pest has one generation per year with obligate diapause. Moreever, this result is in accordance DISCUSSION with Kravchenco et al. (2005) and Saxena et al. (1996). A comparison of the flight peak, the peak of pod borer Results obtained from the number of H.viriplaca taken by oviposition, peak of activity of larvae populations and the light trap, show that this pest has only one flight peak. phenology of plant showed that a period of 13 to 15 days

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Peak population density of small larvae 100 220 90 200 80 180 70 160 140 60 50% of flowering 120 50 100 40 80 30 60 20 Percent of flowering flowering of Percent 40

10 20 larvae small of Number 0 0 2 0 0 4 . 5 . 5 2 0 0 4 . 5 . 8 2 0 0 4 . 5 . 1 5 2 0 0 4 . 5 . 2 2 2 0 0 4 . 5 . 3 1 2 0 0 4 . 6 . 6 2 0 0 4 . 6 . 1 3 2 0 0 4 . 6 . 2 0 2 0 0 4 . 6 . 2 7 2 0 0 4 . 7 . 4 2 0 0 4 . 7 . 1 1

ِ ◌ Date of sampling percent of flowering smal larvae

Figure 6. Comparison the peak population density of small larvae of Heliothis viriplaca with different stage of growth in chickpea.

50% of flowering

220 45 210 200 Flight peak Peak population 190 40 180 density 170 35 160 150 140 Counted eggs 30 130 batch 120 25 110 100 larvae 20 90 80 70 15 Number of small small of Number 60 50 10 40 30 20 5 10 0 moths adult and batch 0eggs of Number 2 0 0 4 . 4 . 2 6 2 0 0 4 . 5 . 3 2 0 0 4 . 5 . 6 2 0 0 4 . 5 . 8 2 0 0 4 . 5 . 9 2 0 0 4 . 5 . 1 0 2 0 0 4 . 5 . 1 5 2 0 0 4 . 5 . 1 6 2 0 0 4 . 5 . 1 7 2 0 0 4 . 5 . 2 2 2 0 0 4 . 5 . 2 3 2 0 0 4 . 5 . 2 4 2 0 0 4 . 5 . 2 9 2 0 0 4 . 5 . 3 1 2 0 0 4 . 6 . 4 2 0 0 4 . 6 . 7 2 0 0 4 . 6 . 9 2 0 0 4 . 6 . 1 4 2 0 0 4 . 6 . 1 5 2 0 0 4 . 6 . 2 1 2 0 0 4 . 6 . 2 8

ِ ◌ Date of sampling Small larvae egg Adult moths

Figure 7. Comparison of flight peak, peak population density of small larvae and counted eggs batch of Heliothis viriplaca with 50% flowering of chickpea.

after the flight peak of H. viriplaca was most appropriate season. Unfortunately, fully grown larvae of H. viriplaca for chemical control. This time period coincided with 50% were parasitized by the parasitic wasp H. hebetor in the of plant flowering. Sequeira et al. (2001) reported end of the season, but by that time most of larvae bored chickpea attractiveness to oviposition of Helicoverpa the chickpea pod. This parasitic wasp is therefore not an moths from as early as 14 days after planting and adequate agent of pest control. In contrast, H. armigera is throughout the growth period. At first, we observed H. multi generational. Consequently, the larvae of second hebetor species in Kermanshah region; but not recorded. generation of this pest are most parasites of H.hebetor . The field studies showed that the population of parasitic Therefore, the over wintering pupa, will be the less for the wasp H. hebetor increased significantly at the end of the next year. This could be one reason that these species

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Table 4. Number of larvae of H. viriplaca parasite by Habrobracon hebetor .

Date Number of larva Number of parasitic larva Percent of parasitic larva (%) 2004.6.7 100 1 1 2004.6.9 100 3 3 2004.6.17 20 8 40 2004.6.28 28 27* 96.43

* Larvae collected from 2600 pod of pea.

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