Carrot fly and hot weather

We would have expected the numbers of carrot fly captured on our traps at Wellesbourne to have increased again by now - to signify the start of the second generation. However, numbers remain low. This may be due to pupal aestivation because soil temperatures have been high for some time.

In some experiments we did many years ago, newly-formed carrot fly pupae were exposed to temperatures of 22-30^oC for various 5-10 day periods during pupal development. Exposure to temperatures of 24^oC and 26^oC caused some, and exposure to 28^oC and 30^oC caused all, of the pupae to delay development. Development was resumend when the temperature was lowered. Pupae were sensitive to high temperatures only for approximately 4-10 days after pupation.

Carrot fly eggs/newly-hatched larvae are also susceptible to hot/dry conditions and mortality is increased. We do not know how much irrigation would reduce the effects of hot weather.

Carrot fly pupae

Rosemary Collier : 09 Aug 2013 11:11 |  Comments (0) |  Report a problem