THE INFLUENCE OF SOME INSECT GROWTH-REGULATORS ON MORTALITY AND FECUNDITY OF THE APHIDOPHAGOUS COCCINELLIDS ADALIA-BIPUNCTATA L AND COCCINELLA-SEPTEMPUNCTATA L (COL-COCCINELLIDAE)

Investigations were carried out to evaluate the influence of some inse ct growth regulators (IRGs) on different developmental stages of Adali a bipunctata and Coccinella septempunctata. The experiment was based o n eggs, larvae and adults reared in laboratory conditions. These stage s were treated with IGRs in 3 ways: 1. by immersing the specimens for 5 sec into a solution of the insecticide tested; 2. by placing the adu lts and larvae of different stages into a small container together wit h two leaves picked up from a tree just treated with the insecticide i n question; 3. by feeding adult coccinellids with aphids contaminated by a recommended concentration of an IGR solution. The experiments hav e shown that the tested IGRS affected all developmental stages of both coccinellid species but the results varied according to stage, way of treating and kind of chemical used. Some of 'the insecticides elicite d a drastical reduction of the fecundity, especially in ladybirds fed with contaminated aphids (e.g. with teflubenzuron, fenoxycarb and fluf enoxuron). Moreover, chlorfluazuron was the most dangerous one for alm ost all larval stages. From the other hand IGRs exerted a relatively l ow influence on adult coccinellids.