Filbert aphids mate in the fall and then lay eggs, which will overwinter on hazelnut trees. The aphids then hatch in the spring and move onto developing buds and shoots to feed. Here are some photos of filbert aphids mating, and also eggs that have been deposited at the bases of buds.
The top two photos show winged male filbert aphids, which appear in the fall, and then mate with the wingless females. A wingless female with an ovipositor is shown in the bottom left of the gallery. The bottom right photo shows small black aphid eggs, which are often laid in protected areas on hazelnut twigs including the bases of buds, catkins, and amongst trichomes on twigs. Photo credits: aphids= Nik Wiman, aphid eggs= Heather Andrews
