Large narcissus fly forecast

Narcissus fly emergence is likely to start soon in the south-west and central and eastern England:

Once they have emerged, adult large narcissus flies need warm sunny days to mate and lay their eggs. Provided these conditions occur, egg laying will start 4-5 days after emergence at the earliest. Mating, and therefore egg-laying, will be delayed if air temperatures are lower than the activity threshold, which is close to 20^oC. The period between egg-laying and egg hatching, after which the larvae invade bulbs, will be about 9-11 days depending on temperatures.

Rosemary Collier : 15 May 2014 22:19 |  Comments (0) |  Report a problem