ABSTRACT

Cotton crop response to varying levels of square loss resulting from tarnished plant bug (TPB) feeding was assessed using standardized COTMAN procedures in a 2-year study conducted in northeast Arkansas. Natural populations of plant bug were augmented with laboratory reared TPB nymphs. Each treatment received different numbers of TPB nymphs over the first 3 weeks of squaring or was untreated or was sprayed with insecticides. Plant bug feeding resulted in as much as 50% shed of 1st position squares by the time of 1st flowers compared to less than 6% shed in protected treatments. Highest levels of shed resulted in significant yield loss; however, square shed levels of 25% were found not to reduce final yield. No differences in numbers of pre-flower sympodia were noted in response to TPB feeding; however, terminal growth after first flowers, as reflected in NAWF measures, was higher where pre-flower shed rates were high, resulting in a delay of physiological cutout and crop maturity. Results from this and other past studies indicate that high yields do not require complete annihilation of all pest insects, and that low to moderate levels of square shed pre-flower are easily tolerated.