Effect of black legume aphid <i>Aphis craccivora</i> honeydew on survival of the parasitoid <i>Microctonus aethiopoides</i>

Abstract

The introduced parasitoid Microctonus aethiopoides (Hymenoptera Braconidae) appears to be an effective biocontrol agent for clover root weevil Sitona lepidus Gyllenhal (Coleoptera Curculionidae) in New Zealand pastures As these pastures lack accessible nectar sources hemipteran honeydew may be the most readily available energy source for the parasitoid Experiments were undertaken to compare longevity of newly emerged M aethiopoides adults caged on white clover firstly with and without black legume aphid Aphis craccivora Kock (Hemiptera Aphididae) and then with additional water and sucrose solution treatments Parasitoids with access to aphid honeydew lived significantly longer (mean longevity 81 days) than those with water or no liquid (both 68 days) but not as long as those fed sucrose solution (109 days) Therefore the abundance of aphids commonly present on clovers may enhance M aethiopoides longevity and therefore efficacy in the field especially in mid spring when host availability is very low

Impact of guttation fluid from perennial ryegrass infected with different strains of Epichloe festucae var. lolii endophyte on Microctonus aethiopoides adult longevity

“…However, feeding was observed at times when the old dry filter paper square was replaced by a fresh square wetted with a test guttation fluid. Also, the overall mean longevity of 5.9 ± 1.3 days on water at 20 o C is similar to that observed previously (Gerard et al 2013) and for M. hyperodae (Phillips 1998). In the final run, parasitoids provided with sucrose solution had a marked increase in longevity (2.4 days or greater) compared to all other treatments (Table 1) so it is postulated that lack of nutrients, rather than dehydration, was the cause of earlier mortality.…”