Warm winter is great for bugs

The warm weather over the past few months was great for farmers in that it allowed them to work in their fields much later than normal. However, the winter has also been kind to the very pests that menace the farmers? crops in the summer.

Iowa State University Crop Specialist Jim Fawcet said the this has been the warmest winter since the early 1900s. He said he?s worried about what the warm weather will mean for the bean leaf beetle and the flea beetle, which tend to be especially bad after mild winters. The flea beetle is responsible for spreading Stewart?s Wilt.

?The beetles hibernate in the soil,? he said. ?If it?s really cold, must of them don?t make it through the winter.?

Fawcet said the beetles don?t really burrow into the soil but rather hide under grass or other refuse. He said that sub-zero temperatures kill most of them, but there haven?t been many sub-zero days so far this winter.

?The flea beetles tend to be a problem in the southern part of the state, but in warm winters they can be a problem for people up north, too,? he said. ?You didn?t use to see bean leaf beetles. We had several warm winters several years in a row for a while and that?s when you saw them. However, the last few winters have been harsh so you haven?t seen them as much.?

Fawcet said that it?s possible that the beetles won?t be so bad this year since this is the first warm winter in several years.

?It may take more than one warm winter to see a big difference in beetle numbers but only time will tell,? he said.

Aphids, another agricultural nuisance, is not affected by winter weather as much because they overwinter as eggs.

?The eggs are more hardy so they can stand the cold temperatures,? he said. ?Then there are pests such as root worms which live in the soil. The air temperatures don?t affect them very much.?

Fawcet said that farmers were worried about dryness earlier in the fall because there was so little rain. The crops need some rain in the fall in order for there to be sub-soil moisture to feed on in the early spring. Fawcet said that southeast Iowa got some rain in November and December which allayed some of the fears about a lack of subsoil moisture.

He said that rains late in the fall may not be helpful if the ground is already frozen because the water runs off the soil instead of being soaked up by it. However, he said the warm temperatures in the late fall allowed those late rains, and even the early snowfall, to be absorbed by the soil.

?Northwest Iowa is very dry because it didn?t get those rains,? he said. ?Southeast Iowa got those rains and now we?re in better shape than we were in October.?

Fawcet said it?s not unusual for the soil to be dry in January. He said that even when the ground is not frozen, snow provides very little moisture. He said a foot of snow has the equivalent moisture of one inch of rain.

?We always want plenty of subsoil moisture,? he said. ?What you don?t want is topsoil moisture. That?s a problem we?ve had for several springs in a row. We?ve had too much spring rain. It would be nice to have a normal spring for once.?

Fawcet said that farmers could at least look forward to not having to deal with much spring flooding since so little snow has fallen this winter.