Survival and reproductive performance of Rhopalosiphum padi (Hemiptera: Aphididae) on maize husk: evidence for a secondary host facilitating seasonal carryover.

The host plant associations of the bird cherry-oat aphid, Rhopalosiphum padi (L.), a major pest of wheat, before and after wheat harvest remain poorly understood. Overlapping growth of maize and wheat may promote R. padi survival and movement between crops. We examined population dynamics and constructed life tables for R. padi reared on wheat seedlings, maize husks, and maize leaves. Field-collected R. padi survived on both maize tissues, but aphid abundance declined sharply on aging maize leaves, while aphids on maize husks developed successfully. Aphids reared on wheat exhibited the fastest development, longest lifespan (27.89 ± 1.20 days), highest fecundity (98.59 ± 5.61 nymphs), and lowest mortality (2.56%). In contrast, aphids transferred to maize leaves showed reduced longevity (19.62 ± 1.16 days), lower fecundity (33.55 ± 2.47 nymphs), and higher mortality (23.73%). No significant differences in some reproductive parameters were observed between wheat- and maize husk-reared aphids, indicating relatively good performance on maize husks. Aphids transferred from wheat to maize experienced fitness costs, while aphids moved from maize husks back to wheat exhibited improved performance. These findings suggest that maize husks offer a comparatively favourable resource microhabitat for R. padi, potentially serving as a secondary host that supports population persistence after wheat harvest.