Integrated management of pink bollworm through mating disruption technique using a sex pheromone formulation offers a practical and ideal approach. Large scale field experiments were conducted during 2005-06 and 2006-07 at agril research station Dharwad to evaluate the efficacy of PB Rope L (Sex pheromone based commercial product) for management of pink bollworm. PB Rope L dispensers @ 200/ha were tied to cotton stalks at pinsquare stage. The performance was compared with the RPP. The mating disruption block registered significantly lower moth trap catches. The extent of reduction was 79.38 and 93.81 per cent over RPP during the consecutive years. The average reduction in green boll damage was 72.62 and 70.11 per cent. The reduction in the larval population in fruiting bodies was 52.34 and 56.70 per cent over RPP. Significant difference with respect to open boll was noticed. The extent of reduction was 68.86 and 66.17 per cent over RPP. The reduction in locule damage was quite conspicuous where mating disruption was exercised. Significantly higher seed cotton yield (32.12 and 40.92 %) was recorded over control (RPP).

Pink bollworm Pectinophora gossypiella (Saunders) is one of the key pests of cotton, emerging as a real threat to cotton cultivation in southern and central parts of India inflicting locule damage to an extent of 55 per cent and reducing the seed cotton yield to an extent of 35 to 90 per cent (Narayanan 1962) ascertained that 75 to 100 per cent bolls are liable to be damaged by this pest. Agarwal and Katiyar (1979) calculated yield loss to an extent of 6525 MT annually. Its infestation causes premature opening of bolls resulting in stained immature fiber (Agarwal et al., 1984).Significant reduction in fiber properties of lint from infested bolls has been observed by Shiva Subramanian, 1991.

The severity of pink bollworm infestation causes both qualitative and quantitative loss heavily and it is much more pronounced in interspecific hybrids which are important sources of extra long staple cotton and is of utmost importance from the point of view of textile industry and export. Pink bollworm endemic nature and reproductive capacity seriously challenged all control efforts. Besides this pest is inaccessible to routine methods of pesticide control and even conventional IPM components do not provide acceptable level of management. As a possible means the use of certain behavior modifying chemicals are potentially a viable alterative to the use of conventional insecticides and reached the stage of commercial production. Sex pheromone formulation of pink bollworm containing ZZ/ZE-7-11 Hexa decadien-1-yl-Acetate as active ingredient has been commercially used world over as an integrated component of IPM for successful management of PBW incidence in particular and other insect pest in general in cotton. Insect pest management through mating disruption technique using sex pheromone offers a practical and ideal approach to combat the above complex situation prevailing in cotton ecosystem (Patil.et al.,2004). Considering the severity of this dreaded pest, effort has been made to find out a suitable control measure a large scale field experiment was undertaken at ARS, Dharwad farm to evaluate the efficacy of PB Rope L [Sex -pheromone formulation of Pink bollworm manufactured by Shin-Etsu Chemical Co. Ltd., Japan. supplied by New chemi industries Ltd., Mumbai, India during 2005-06 and 2006-07 cropping periods.

Materials and Methods

Large scale field trials were conducted during 2005-06 and 2006-07 in farmers’ field to evaluate the suitability of PB Rope L for the management of pink bollworm. To compare PB Rope L in conjunction with insecticide schedule for the control of pink bollworm on cotton, field experiments were conducted at Agricultural Research Station, Dharwad farm during Kharif 2005-06 and 2006-07 on an area of 20 hectares. The popular inter specific cotton hybrids viz., RAHB-87, DHH-11, Sahana and Bt genotypes on an a area of 20 hectare were growth. However, observations were recorded only in RAHB-87 block which was compared with farmers field at Yammatti (Tq: Kalagatagi) where RAHB -87 was grown on an area of five acres. The treatments followed in the experiments were as detailed below.

Block A- PB Rope L @ 200 / ha + ETL based/chemical application (Table-1)

Block B- Control (No PB Rope L) farmer’s schedule of spray only (Table-1)

PB Rope L dispensers containing synthetic sex pheromone of pink bollworm [ZZ/ZE-7,11-Hexadecadiene-1-yl-Acetate] were tied manually by twisting the dispenser around central shoot of the cotton plant at first pin square stage (40- 45 days after sowing). The performance of PB Rope L in combination with plant protection schedule in reducing the pink bollworm incidence was compared with recommended plant protection where there was no target specific treatment for pink bollworm management. These fields were located 2-3 km away from experimental area.

Plot A: PB Rope L dispensers @ 200 / ha were tied and pesticide application was made strictly based on economic threshold level of pink bollworm moth trap catches.

Plot B: farmers applied pesticides as per their choice and agronomical practices and cotton hybrid grown were similar to that of Plot A.

A common spray of Acetamiprid 20 SP @ 0.2 g / l was applied to protect the crop from sucking pest complex at 25th and 40th days after sowing. Similarly to protect the crop from bollworms (Earias spp. and Helicoverpa armigera) recommended bollworm management sprays were initiated from 45 days after sowing and continued at 10 to 12 days interval till the bollworms activity ceased.

Results and discussion

The bio efficacy of PB Rope L in reducing the PBW incidence was evaluated by recording pheromone trap catches, green boll infestation, larval population, open boll damage, locule damage at harvest and by comparing the seed cotton yield.

Observations on moth trap catches were initiated at weekly interval starting from first week of September and confined up to January during both the cropping period. The density of male moths varied to a greater extent between both the blocks with the advancement of cropping period. Significantly lower moth trap catch was observed in block ‘A’ where target specific treatment PB Rope L was applied in addition to regular plant protection schedule. The number of moths trapped in block ‘A’ ranged from 1.80 to 18.40 with a mean of 5.92/trap/night as compared to 7.00 to 110/trap/night with mean of 28.72 moths and 0.07 to 3.63 moths with a mean of 1.03 as against 4.26 to 66.82 with a mean of 21.69 moths/trap/night during 2005-06 and 2006-07 respectively. The extent of reduction in moth trap catches was 79.38 and 93.81 per cent during the respective years. Mean trap catches during the consecutive years was 24.69 and 3.41 with a reduction of 86.18 per cent (Table-2). The efficacy of PB Rope L in suppressing the activity of pink bollworm was quite convincing in terms of moth trap catches over the season. These findings are in agreement with Patil et al., (2004) who recorded an average of 0.8 moths/ trap/ night when PB Rope L was used @ 200 dispensers/ ha as against 2.6 / trap / night in control plots.

Significant difference with respect to green boll infestation was observed between the blocks (Table-3). Initially the numbers of green bolls damaged were found to be less. As the season advanced the green boll damage increased reaching peak during January moth.

The mean percentage of green boll damage in block ‘A’ was 8.00 and 7.50 with reduction of 72.62 and 70.11 per cent during 2005-06 and 2006-07 respectively. Over the season, the extent of reduction in green boll damage was 72.04 per cent over RPP alone where there was no target specific treatment for PBW management. Reduced incidence on green boll was the reflection of differential larval population that prevailed in blocks with and without PB Rope L. Pink bollworm made its first appearance during September month during the consecutives seasons and maximum number of larvae were observed during January month. Significantly, lower population to larvae was recorded in treated block (9.76 and 8.40/ 50 bolls) as compared to control block where ETL based plant protection alone was taken (20.48 and 19.40/50 bolls). The extent of reduction in larval population was 52.34 and 56.70 per cent over the control block during 2006-05 and 2006-07 respectively. Over the season (Table 4). The mean larval population in PB Rope L treated block was 8.75/50 bolls as against 19.60 in control block with a reduction of 55.35 per cent Collor et al., (2004) reported effective control of pink bollworm with controlled release of formulation of sex pheromone of PBW mating disruption technique. These findings are also in close agreement with the findings of Qureshi et al. (1988) who observed a significantly low incidence of pink boll worm larvae in green bolls (1.67%) while using PB Rope L @ 55 g ai / ha. It was interesting to note that damage to open boll was also lowered by the treatment containing PB Rope L. As against 47.83 and 44.02 per cent open boll damage in control block, 14.89 and 14.89 per cent was recorded in treated blocks during the respective years (Table -5). The mean PBW incidence on locule basis was significantly low i e., 11.55 and 11.81 per cent in PB Rope L block as compared to 48.56 and 47.97 per cent in control block during the consecutive seasons. The extent of reduction was 76.21 and 75.38 per cent respectively with a mean of 75.75 per cent (Table 5). These findings are in confirmly with the observation of Sohi et al., (1999) who recorded significantly low per cent open boll and locule damage in the fields treated with mating disruption along with the insecticide compared to field treated with insecticide alone who reported less PBW infestation in green bolls and locules in PB Rope L treated block.

The present studies conducted during 2005-06 and 2006-07, for the management of pink bollworm using PB Rope L @ 200 dispensers/ha applied at pin square stage of cotton proved to be promising option in endemically infested areas. It is claimed that PB Rope L when tied to plants, natural instinctive flight behaviour of male moths bring the adults in more prolonged contact with treated plants. Depletion of male moths in the environment results in reduction of laying fertile eggs and thus brings down larval infestation and crop damage. Significantly higher yield of 22.95 q/ha was harvested from PB Rope L treated block accounting for 32.12 per cent increase over RPP block (17.37 q/ha). Further during 2006-07, the seed cotton yield of 23.52 q/ha with an increase of 40.92 per cent was recorded in PB Rope L treated block. Pooled data revealed that significantly higher (23.24 q/ha) seed cotton yield was harvested in block as against 17.03 q/ha from RPP block with 36.46 per cent increase (Table 6). Net return from PB Rope L treated block was Rs.30773 and Rs.31273 as against Rs.220013 and Rs.21353 in RPP during 2005-06 and 2006-07 respectively (Table 7). The field study conducted at Raichur, Karnataka also revealed that the application of PB Rope L along with insecticidal spray recorded lower open boll and locule damage and higher seed cotton yield (Patil et al., 2004). In the present investigation, there is a marked increase in yield as well as net returns. Considering the net returns and yield advantage, application of PB Rope L in addition to the regular plant protection schedule is found to be economically viable and promising option for pink bollworm management.

References:

AGARWAL, P.A., GUPTA, A.P AND GARG, D.O., 1984, Cotton Pest Management. Research Co-publications, East Azad Nagar, Delhi, p.941.

AGARWAL, R.A., AND KATIYAR., 1979, An estimate of losses of seed kapas and seed due to bollworms on cotton in India. Indian Journal of Entomology.41 (4) : 143-148.

COLLOR U.R., QUIJO, J. L AND GALVEZ MANZANO V 2003 , Mating disruption strategies for the control of pink bollworm in cotton fields. Boletin de Sanidad vegetal, Madrid, Sapin. Pages 28 (7), 193-198.

GRANT, G.G., 1978, Field trials on disruption of pheromone communication of Tussock moths. Journal of Economic Entomology, 71: 453-457.

NARAYANAN, E.S. 1962, Biology and Method of Control of Some Important Insect Pests of Cotton in India. Indian central Cotton Committee Publication, Bombay, p.44

PATIL, B.V., BHEEMANNA, M., HANCHINAL, S.G. AND ANANDKUMAR, V. 2004, Management of Cotton Pink bollworm using PB Rope L mating disruptant. In The proceedings of International Symposium on “Strategies for Sustainable Cotton Production- A Global Vision” held at University of Agricultural Sciences, Dharwad, Karnataka (India) from 23-25 November 2004. pp:172-175.

QURESHI, Z.A, M.D. ARIF, N. AHMED AND NAZEEBULLAH 1988, control of pink bollworm by mating disruption technique. Pakistan. J.Sci.Ind. Res., 31, 711-713.

SHIVASUBRAMANIAN, P., 1991, Ecology host plant insect interactions as management of pink boll worm, y Pectinophora gossypiella (Saunders) on cotton .Ph.D. Thesis, Tamil Nadu Agricultural University, Coimbatore.

SOHI, A.S., JAGINDER SINGH AND RUSSEL, D., 1999, Further studies of mating disruption in pink bollworm P.gossypiella (Saunders) using sex pheromone as a component of IPM programme in irrigated cotton fields in Punjab. Pest Management and Economic Zoology, 7 (1): 31-38.

Table 1: Plant protection schedule followed in both experimental blocks

	Block A (RPP + PB Rope L)		Block B (RPP alone)
Sl. No.	Chemical sprayed	Dosage	Chemical sprayed	Dosage.
1.	Endosulfan 35EC	875 g/ha	Endosulfan 35EC	875 g/ha
2	Quinalphos 25 EC	500 g/ha	Quinalphos 25 EC	500 g/ha
3.	Acephate 75 SP	700 g/ha	Acephate 75 SP	700 g/ha
4.	Profenophos 50 EC	500g/ha	Profenophos 50 EC	500g/ha
5.	λ-Cyhalothirn 5 EC	25g/ha	λ-Cyhalothirn 5 EC	25g/ha
6.	Indoxacarb 15 SC	0.5 L/ha	Indoxacarb 15 SC	0.5 L/ha
7	PB rope L	200 dispensers /ha	--	--

Common spray schedule followed for sucking pest management.

1. Spraying of Imidacloprid 200 SL @ 100ml/ha

2. Spraying of Acetamiprid 20 SP @ 50 g/ha