Large increases in mosquitoes are usually the most immediately obvious insect problem following heavy summer rainfall. Floodwater species, notably Aedes vexans, lay eggs at the edge of temporary water and egg hatch initiates when these areas are flooded. Since the life cycle takes about 10-12 days to complete, large pulses of biting adults follow these rains. Such sites abound following flooding. Black flies, on the other hand, develop in running water.
Streamlets running through fields following flooding are an ideal habitat for their development.
To the extent that such conditions exist a surge in black flies can be expected a few weeks after flooding. Pests favored by improved host plant condition. Russian wheat aphid and several other pests use volunteer wheat as a bridge to the winter wheat crop. With the high moisture abundant volunteer wheat will be available. With grasshoppers the effect could be mixed.