Pesticide & Defoliant Reduction in Cotton Using Thermal Cultivation

1. Pesticide & Defoliant Reduction in Cotton Using Thermal Cultivation Robert McGee T.-X. Liu TAES-Weslaco

2. Background • Current cotton defoliation practices • Too much chemical defoliants or desiccants: Dropp, Def, Folex, Quick Pick, FreeFall, Ginstar, LeafLess, Harvade, Aim, Finish, CottonQuick, Ethephone, KleanPik, ET, … • Hard to manage the crop conditions, weather, timing, rates • Sticky cotton caused by sucking insects (whiteflies, aphids) • Costly: benefits, environment, …

3. Background • Alternatives to defoliants - Thermal defoliation or heat treatment • Be independent of the weather • Reduces the need for insecticides • Eliminates the increased use of harvest-aid chemicals • Protects the crop from insect sugar deposits. • Minimize trash content, fiber damage and staining of the lint • Enable growers to better manage harvesting operations

4. Objective • To evaluate the suitability and performance of thermal defoliation as an alternative technology to chemical defoliation and pesticides

5. Materials and Methods • Cotton: BollGuard II® - RoundUp Flex® variety (FiberMax 9063 BII F) • 40” row • Planted: 28 Feb. • Harvest-aid treatments: Chemical and thermal • Harvested: 20 July

6. Chemical defoliant-treated plots on the left side.

7. Harvest-aid Treatments

8. Insects and Sampling • Sweetpotato whitefly, Bemisia tabaci • Cotton aphid, Aphis gossypii • Boll weevil, Anthonomus grandis • Others

9. Insect Sampling • Sweetpotato whitefly • Adult whiteflies were counted, using the leaf turn method, on the third leaf from the main terminal of 10 plants in each plot • Whitefly nymphs counts were made from the fifth leaf of 10 plants in each plot

10. Flying whiteflies (see dark area)

11. Insect Sampling • Cotton aphid • All aphids were counted from the terminals of 10 plants in each plot

12. Insect Sampling • Boll weevil • Dropped square counts were made by picking up all dropped squares/bolls in a ten foot length of row within the treatment plot • Count adults, larvae, pupae.

13. Insect Sampling • Another set of counts were made by placing a large trash bag over a plant in the treatment plot and vigorously shaking the plant • Counting the insects collected. • 5 plants per plot.

16. Harvest and Sampling • Machine picked • 25 ft row in each plot • Seed cotton weighed • Other parameters: • HVI (micronaire, length, uniformity, strength, elongation, Rd, +b and leaf) • Trash • Sugar

17. Insects direct-counts on plants No. whitefly adults per plant

18. Insects direct-counts on plants No. whitefly nymphs per leaf

19. Insects per plant (bagged) No. whitefly adults per plant

20. Insects per plant (bagged) No. boll weevils per plant

21. Boll weevils and damage(10’ row) No. boll weevils/10’ row No. squares damaged/10’ row

22. Sugar contents* No significant differences among the treatments *International Textile Center, TTU

23. Yield and fiber quality etc.* No significant differences among the treatments: length, uniformity, elongation, Rd, +b and leaf. *International Textile Center, TTU

24. Foreign matter* *International Textile Center, TTU

25. Summary • Thermal treatment did not adversely affect cotton quality • Thermal treatment reduced adult whitefly populations, possibly due to mortality • Possible increase in return the net loan price for pound of lint cotton

26. Thank you &Questions?