Influence of Moisture on Winter Survival of the Pink Boll worm12

Abstract

The effect of natural and simulated patterns of rainfall on the winter survival of the pink boll worm, Pectinophora gosspyiella (Saunders), was studied for 2 years in outside cages at Waco, Texas. The effect of temperature and level of soil moisture on survival of diapauses larvae was studied in bioclimatic cabinets, programmed to simulate the December 1960-March 1961 conditions of temperature and soil moisture level at Waco and Heavener, Oklahoma, areas of generally high and low winter survival of the insect, respectively. In the outside cages, survival from the buried bolls decreased when moisture level was increased during December-January or February-March; high levels of moisture during both periods, i.e., from December through March, decreased survival still further. High levels of moisture during April-May had little or no influence on survival regardless of the date when the boll was buried. In the bioclimatic cabinets, moderate temperature and a moderate level of soil moisture (1670) reduced survival compared with that obtained at a low level of soil moisture (8%). At low temperatures there was no significant difference in survival at the 2 levels of soil moisture.