Current Indian Status

Resistance to insecticides was monitored either through Discriminating dose assays ( use of a single dose that kills 99 % individuals of a susceptible strain ) to indicate per cent resistant individuals in a field population or through log dose probit assays to derive the LD50 which indicates the dose required to kill 50 % individuals in a population. The LD50 of the field population is then compared to that of the susceptible strain and expressed as resistance in x fold. Resistance to pyrethroids continues to be high with levels of 108 to 7220 fold in almost all parts of the country. Earlier Armes et al., (1996) had reported resistance factors of 5 - 6500 fold to pyrethroids in field populations of Helicoverpa collected from all parts of the country. Pyrethroid resistance is wide spread in India, at high levels in Maharashtra, Punjab, AP and Tamilnadu Resistance levels during the entire season are usually high with minor exceptions during early cotton season and appear to be independent of the pyrethroid use pattern ( Kranthi et al., 1997 ). The problem is still most severe in the coastal belt of AP. When used alone pyrethroids are no longer excepted to be effective against Helicoverpa except on larvae less than second instar stage. However, resistance assays carried out against the pink bollworm and spotted bollworm indicated that these were still susceptible to pyrethroids. Pyrethroid resistance levels during 1993 - 99 have been high all over India. In most parts of the country, survival frequencies to that discriminating dose of cypermethrin 0.1 ug are still found to be 95 - 100 %. Despite the steady decline in the preference for pyrethroids in cotton pest management over the past two - three years, resistance to pyrethroids does not appear to be on the decline. The '93 - '99 data on 'in - season' changes in pyrethroid resistance at all centres, however, indicates that resistance levels were relatively lower during the cotton season ( October - November for A.P., Coimbatore and Maharashtra and August - September for North ). This information supports the idea that pyrethroids could still be used on cotton against Helicoverpa infestation during the period mentioned above. This could as well be meaningful for better utilization of these compounds as the pyrethroid application during this time also coincides with the early infestation of the pink bollworm.

                         IRM in cotton pests in 'a nut shell'

  • Cultivate 'sucking pest tolerant' cultivars and/or seed treatment
  • Zero insecticide till 60 days
  • Based on economic threshold the following simple ' window strategy can be adopted
  • No 'organophosphate' till 90 days
  • Endosulfan - not beyond 90 days
  • Biorationals eg: HaNPV, neem,etc'if applicable' at 70-90 days
  • Pyrethroid only after 110days

source : Sustainable Cotton pest management through IRM, CICR tech bull no.1/1999

Resistance to Endosulfan was found to be 1 - 14 fold in the field populations tested. Armes et al., (1996) had reported resistance factors of 2 - 28 fold and suggested that field control failures could be caused due to resistance factors as low as 5 -1 0 fold. Seasonal averages of resistance to endosulfan have been very high throughout '93 - '99 at Coimbatore (45 - 57 %), Guntur (47-67 %) and Nagpur (40 - 46 %), but relatively low in Rangareddy district (29-35%) and parts of Punjab and Haryana (15 - 20 %). However a closer look at the dynamics of resistance for all seasons of '93-'99 reveals that, at all the monitoring sites
( except Coimbatore ), resistance to endosulfan has been low (20 - 25 %) at the beginning of cropping season and generally increases to about 40 - 50 % by the end of November when spraying on cotton ceases. At Coimbatore resistance to endosulfan appears stable at about 45 - 50 % (with minor exceptions) throughout the season during all the years. Hence endosulfan is being recommended as an early season insecticide. Resistance to quinalphos was found to be low to moderate at 1 - 29 fold, for the field populations collected recently during '98-'99. Resistance was higher in the coastal belt of Andhra Pradesh and some pockets of Central India. Earlier quinalphos resistance has not been reported to exceed 2 - 9 fold in field populations ( Armes et al., 1996 ). Resistance to quinalphos has been high at Guntur (45 - 66 %) and Coimbatore (44 - 48 %), but low (about 20 - 25 %) in Punjab, Rangareddy and Nagpur. It was also observed that resistance levels to Ops and endosulfan increase in the season depending on the use of these compounds. Organophosphates such as quinalphos, chlopyriphos and profenophos can be used during the peak reproductive phase of the crop. Resistance to menthomyl was 1 - 22 fold, with higher levels in the coastal belt of Andhra Pradesh and some parts of Central India. Resistance to methomyl was monitored at all sites ( except Coimbatore ) during '97-'99 seasons. Resistance appears to be gradually on the rise with recent increase in use of this chemical for Helicoverpa control. Resistance increases were similar to that of organophosphates, for example resistance was moderate ( 31 - 40 %) in September, October and December but increased later to 69% in February. Armes et al. (1996) report resistance levels of 2 - 38 fold to methomyl in different parts of India, with highest at 162 fold in Guntur. The carbamates can be used as a single spray prior to the pyrethroid window.

IRM Strategies

Formulating resistance management strategies for Indian conditions has been fairly complicated. The diversity and complexity of cotton farmers, cultivation practices and cropping situations has always posed a challenge. The strategies need to be uncomplicated, simple, robust, available, affordable, compatible with current cropping practices, easy to understand etc. Most IPM proponents would now agree that some of the biological intervention components of cotton IPM have been tricky due to their inconsistency in performance and importantly their non - availability. Insecticides in most situations have usually been found to be counterproductive due to resistance and resurgence problems. The current strategies hence blend all crop production practices to incorporate proper use of insecticides to ensure that each of these groups are applied at such time of the cropping phase when 1. Resistance is low, 2. Natural enemy populations are least disturbed and 3. Different groups of chemicals are alternated.

Selection of cultivar for Central & South India

Recommended hybrids : NHH - 44, PKV Hy - 2, JK Hy - 1, JK Hy - 2, H - 8, H - 10, Ankur - 651
Recommended varieties : LRA - 5166, Anjali, PKV - 081
Desi types : AKH - 4 , AKH - 8401

Selection of cultivar for North India.

Early maturing : F - 846, F - 1378, LH - 1556, F - 2054, H - 1098
Recommended hybrids : Omshankar, Fateh, Dhanalaxmi.
For CLCV prone areas: RS - 875, LHH - 144, Anjali, LRA - 5166, All desi types ( LD 327, HD - 107, LD - 491)
Resistant / tolerant to Jassids : Bikaneri Narma, H - 777, RS - 875, RST - 9, F - 5- 5, Fateh.

Cultivation Practices Optimised for Better Pest Management

  • Hybrids must be grown in medium - deep soils having good drainage.
  • Early sowing on ridges and furrows, especially in areas with drip facility, could be adopted.
  • Application of weedicide Stomp 30 EC or Basalin @ 45 EC 2.5 lt / ha and harrow immediately to prevent degradation.
  • Harrowing must be done twice after pre - monsoon showers and field should be levelled.
  • Prepare a good seed bed to ensure good plant stand.
  • Grow only arboretum cotton in CLCV hot - spot areas.
  • Only recommended varieties / hybrids from reliable sources must be procured.
  • Apply 10 - 15 cartloads of well decomposed compost or FYM / ha before sowing.
  • In North, sowing can be done at a row spacing of 67.5 cm with 30 cm plant - plant spacing or preferably wider for varieties and 75 cm for hybrids. In South and Central zones sowing can be done at a row spacing of 90 cm with 60 cm plant - plant spacing for hybrids, 60 x 30 cm for varieties and 45 x 20 for Desi cultivars.
  • Fertilizers should be applied @ NPK 60:30:30 for varieties and 90:45:45 for hybrids under rainfed situation. For irrigated cotton NPK should be applied at 90:45:45 for varieties and 120:60:60 kg / ha for hybrids. Fertilizer should be given in three splits, the last to be given before boll - set.
  • In Central and South India sowing must be completed by the first week of July. In North India it is preferable to complete sowing operations by the third week of May.
  • Gap filling must be completed within 10 days after sowing.
  • Thinning should be done within 20 days after sowing.
  • First hoeing can be done 30 - 40 days after sowing followed by second after 15 -20 days.
  • Cowpea can be sown either as bund crop or intercrop and has been found source to natural enemies of sucking pests, which also assist in keeping sucking pests of cotton in check.
  • Do not stack cotton stalks near fields.
  • Immediately after the season allow animal grazing in fields and ensure timely removal and destruction of cotton stubbles, followed by deep ploughing to expose the carry - over population of bollworms.
  • Delint the seed with 100 ml sulphuric acid / kg seed for two minutes, wash with water and soak for two minutes in sodium bicarbonate (5g / ltr water).
  • Treat seeds with Ceresan wet or Agallol @ 1 g / ltr water.
  • Treat seeds with Captan or carbendazim @ 2g / kg.
  • Destroy weeds such as Datura metel and Legascea mollis near fields. These support Helicoverpa populations during off - season. Destroy weeds such as Sida, Abutilon and Xanthium before sowing to reduce CLCV incidence.
  • Avoid growing American cotton in orchards.
  • Avoid growing tur, moong and bhendi ( ladies finger ) in and around cotton field as these harbour insect pests.
  • Crushing of cotton seeds should be completed by end of April, or fumigate seeds with celphos @ 3g / cubic meter.

Vegetative Phase

  • Seed treatment ( Carbosulfan 50 g / kg seed ) also helps in delaying the first spray ( Imidacloprid 7g / kg seed was found useful for hybrids in protecting the crop against jassids upto 40 - 60 days ).
  • Grow sucking pest tolerant genotypes. It helps in delaying the first spray, thus conserving the initial build - up of natural enemies. Some Jassid tolerant cultivars need not be treated with insecticides and are capable of protecting themselves from sucking pests. It is possible to avoid spraying for at least two months for some susceptible genotypes treated with Imidacloprid or carbosulfan.
  • Jassids and Aphids cause maximum damage during vegetative period of the crop. But, populations of Lady bird beetles, Syrphids and Chrysoperla carnea are also generally high and assist in reducing the pest load.
  • Do not use broad spectrum insecticides such as phosphomidon, dimethoate, monocrotophos, metasystox, acephate or any other insecticides belonging to the organophosphate group, as they strongly disrupt natural enemy populations. Avoidance of organophosphate insecticides for the first three months helps in buid - up of entomophage populations such as Chrysoperla, Campoletis chloridae, Microchilonis curvimaculatus, Tachinids, Apanteles, Orius spp. And Podisus spp., bugs etc, which contribute to the management of Helicoverpa.
  • Do not use any insecticide except NSKE + neem oil or endosulfan ( as emergency option against jassids at 2 / leaf, and aphids 50 / leaf ) against jassids or aphids within three months of sowing. Helicoverpa incidence can be noticed in late vegetative phase of the crop in some fields, but the infestation is very low and sporadic and does not warrant intervention.

Early Reproductive Phase

  • Spotted bollworm can cause damage to growing points in Central and South India, but does not cause economic losses. However, pink and spotted bollworms are important pests in north and need to be managed. Set up pheromone traps @ 5/ha for pink bollworm in North India. Eight moths / trap / night for three consecutive nights is the action threshold.
  • Do not use any unregistered compounds such as botanical extracts, neem formulations etc. It is better to use neem oil or aqueous extracts of 25 Kg neem seed kernel /ha, instead of any commercial formulations.
  • Helicoverpa incidence starts in this period. Scouting must be done in at least 50 plants per hectare.Thresholds of 25 larvae/50 plants should be considered for spray of endosulfan.
  • Use of endosulfan should be encouraged only as early season spray against Helicoverpa armigera as resistance levels have been found to be invariably low early in the season. Edosulfan is also relatively less toxic to natural enemies.
  • In North India, pyrethroids may be used as initial sprays, if Helicoverpa egg population @ more than one egg per plant is also noticed simultaneously along with an attack of spotted and pink bollworms. It would be advisable to take up not more than one application of pyrethorid before mid - September. Pyrethroids have strong contact action on all lepidopteran moths; are effective on younger larvae and are ineffective after mid - September due to increase in resistance levels and also due to presence of all stages of larvae. It is advisable to add 1 litre / ha of Sesamum oil to pyrethroids as it helps in counteracting resistance. Sesamum oil should never be mixed with any other group of insecticides.
  • Pyrethroids should be used only once. Synthetic pyrethroids either as over dose or repeated sprays lead to excessive whitefly flareup.
  • Set up pheronmote traps @ 5 / ha for H.armigera to identify brood emergence.
  • It has been found useful to spray 2 % DAP at 80 - 90 days after sowing.

Peak Reproductive Phase

  • American bollworm causes maximum damage during peak reproductive phase.
  • Resistance levels against certain organophosphate group of insecticides (Quninalphos, Chlorpyriphos & Profenophos) and carbamates such as thiodicarb have been found to be relatively lower in most population tested. Hence, it is preferable to use these as effective larvicides during mid - season (Aug - Sept for North and Sept - Oct for Central and South India) based on ETLs (20 larvae / 20 plants ) when the situation warrants.
  • Pyrethroid resistance is high in many parts of India. However, pyrethroids are still effective against spotted and pink bollworm. In South and Central zones pyrethroids can be used after second week of October to target Helicoverpa and a simultaneous initial infestation of the pink bollworm.
  • Pink bollworm infestations are usually high during November in South and Central zones, but are rarely noticed by farmers. It is advisable to use one application of any pyrethroid at a threshold level of 8 moths / trap./ night for the three consecutive nights in pheromone traps. It must be remembered that pheromone septa need to be changed once a fortnight.
  • In South and Central zones during outbreaks years, Helicoverpa may persist till second week of November sometimes. Based on thresholds of 20 larvae / 20 plants / acre, carbamate insecticides such as Thiodicarb may be used during this period.
  • In Andhra Pradesh, egg batches of Spodoptera must be handpicked. Light traps are very effective in Spodoptera management and must be used. Other strategies such as SNPV can also be deployed for effective management of Spodoptera.
  • Insecticides such as monocrotophos are not effective against either Helicoverpa Spodoptera and must be avoided either alone or as mixtures.

Some General Strategies of IRM

  • Handpicking of larvae 2 - 3 days after insecticide sprays effectively eliminates any surviving population which can cause future resistance problems.
  • Always use insecticides as need based applications as per threshold levels. The keys to obtain better result from the use of insecticide are:
    Right time - use insecticides - only when the need arises
    Right chemical - choose - appropriate insecticide
    Right dosage - use - only recommended dose
    Right method - use - proper sprayers and spray methods.
  • Always target younger stages of Helicoverpa as younger stages of resistant larvae are known to get killed at normal recommended doses.
  • Rotation of chemical groups helps in preventing the build of resistance against most insecticides, especially carbamates, organophosphates and endosulfan.

IRM Strategies for Cotton Pest Management - North India

 
May-June
July
August
September
October
November
Insect Pest

Jassids, Aphids

Jassids, Aphids Thrips Pink Bollworm, Whiteflies, Jassids

Helicoverpa, Pink Bollworm, White Flies

Pink Bollworm, Helicoverpa Red Cottonbug
Economic Threshold Level   Jassid - 2/leaf Thrips-50/leaf

Whitefly-10 flies/leaf Pink bollworm-5%damaged fruiting parts Helicoverpa 20 larvae/20plants 10% damaged bolls  
Manage ment options Grow jassid resistant genotypes

Endosulfan (emerg. option)

 

Trochogramma/ HaNPV Endosulfan/ pyrethroid Quinalphos/ Chlorphyriphos Methomyl/ Thiodicarp  
Crop Stage Vegetative Vegetative Squares & Flowering & Bolls Squares & Flowering & Bolls Squares & Flowering & Bolls Bolls
Crop Age 0-30 days 30-60 days 60-90 days 90-120 days 120-150 days 150-180 days

IRM Strategies for Cotton Pest Management - Central and South India

             
  July August September October November December
Insect Pest Jassids, Aphids Jassids, Aphids Thrips Helicoverpa, Whiteflies, Jassids Helicoverpa, White Flies Pink Bollworm Pink Bollworm, Red Cottonbug
Economic Threshold Level   Jassid - 2/leaf Thrips-50/leaf Helicoverpa 10 larvae/20plants Helicoverpa 20 larvae/20plants 10% damaged bolls  
Manage ment options

Imadacloprid as seed treatment for hybrids

Grow jassid resistant genotypes

Endosulfan or neem seed extract

 

HaNPV Endosulfan Quinalphos/ Chlorphyriphos/ profenofos Methomyl or thiodicarb Pyrethroid + sesamum oil
Crop Stage Vegetative Vegetative Squares & Flowering & Bolls Squares & Flowering & Bolls Squares & Flowering & Bolls Bolls
Crop Age 0-30 days 30-60 days 60-90 days 90-120 days 120-150 days 150-180 days

Source : 1. Sustainable Cotton pest management through IRM, CICR tech bull no.1/1999
2. Insecticide Resisitance management (IRM) stategies for cotton pest, Directorate of Cotton Development, Mumbai

 

 

Information compiled, Page designed and developed by M. Sabesh, CICR