EFFECT OF HYDROXAMIC ACIDS ON FEEDING-BEHAVIOR AND PERFORMANCE OF CEREAL APHIDS (HEMIPTERA, APHIDIDAE) ON WHEAT

The feeding behaviour of five cereal aphid species in wheat seedlings (measured by the time taken by an aphid to penetrate the phloem and th e time spent in committed pholem ingestion) and their performance (mea sured as mean relative growth rates) were determined as a function of hydroxamic acid concentrations in the seedlings. Lower mean relative g rowth rates and higher times to attain a committed phloem ingestion we re associated with higher hydroxamic acid values. Duration of committe d phloem ingestion was not influenced by hydroxamic acid values.