Environmental conditions in the Midsouth in 1987 and 1988 resulted in an unusual amount of physiological fruit shed at the lower fruiting sites on the cotton plant. The plant reacted by carrying an unexpected number of fruit at the middle and upper fruiting sites through to open bolls. Additionally, in 1987 and 1988, the largest bolls were not at the fruiting site 4.1 or 5.1 as expected but much higher at 8.1 or 9.1. And, the largest bolls were smaller than expected.

Midsouth cotton growers have changed the way they grow cotton. They used to accept a considerable amount of insect feeding during the first 4 to 6 weeks of squaring. That practice has been changed. The results are that they are taking more fruit per plant through to open bolls. And the boll size is smaller. Under these conditions, PIX-treated cotton tended to reduce the amount of physiological shed, set more fruit, retain more fruit, resulting in more open bolls that on the average were smaller.