Termination of Late Season Cotton Fruiting with Growth Regulators as an Insect-Control Technique1
- D. L. Kittock,
- Jack R. Mauney,
- H. Fred Arle and
- L. A. Bariola2
A technique is proposed for reducing the number of overwintering pink bollworms [Pectinophora gossypiella (Saunders)] by reducing their food supply late in the year. This is done by using growth regulators that prevent formation of new cotton (Gossypium sp.) bolls late in the season, but do not affect development of existing bolls or vegetation. Since most of the late-season bolls do not mature, the effect on lint yield would be minimal.
Three chemicals, (2-chloroethyl) trimethyl ammonium chloride, (CCC); dimethylamine salt of (2,4-dichlorophenoxy) acetic acid, (2,4-D); and 2-chloroethylphosphonic acid (Ethephon) were used. They were sprayed on cotton late in August and early in September. Each of the chemicals reduced the number of green bolls remaining after harvest by more than 90% at one or more dates in one or more tests. In most cases, lint yields were also reduced. In limited observations, we obtained 87 to 96% reduction in diapausing pink bollworm larvae from these treatments.
The effects of Ethephon on seed and fiber quality were too severe to warrant its further use. Residue of 2,4-D in seeds reduced germination. CCC reduced fiber strength in two of four tests. Further testing of the last two chemicals and evaluation of other chemicals are warranted.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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