Total carabid counts were generally higher in the cyromazine treated area versus the chlorpyrifos treated area of a field. However, each of the carabid species counted did not have higher numbers in the cyromazine areas. Total staphylinid counts were also more numerous in the cyromazine areas at all sites in the second year. Count comparisons of other coleopterans and other arthropods were made. The patterns of beetle activity peaks were examined.

Trenches were used to increase and decrease ambient carabid concentrations in an onion field. The relative survival of onion plants on which maggot eggs had been placed did not differ between the high and low carabid concentrations. At harvest, the number of eggs that survived did not depend on the carabid concentration treatments. However, eighty percent fewer maggots survived in the treatments with higher carabid concentrations.

Cyromazine and chlorpyrifos were tested on a variety of soils for control of onion maggot and for possible effects on onion germination and growth. These tests were done by growing onions with these insecticides and with a no insecticide control on different soils in two greenhouse studies and one field study. These results indicate that cyromazine does not differ from chlorpyrifos in its efficacy at the different soil organic matter contents tested. However, soil organic matter content does effect the growth of onions and the performance of the insecticides.