Southwest Michigan vegetables regional report – Aug. 21, 2013
Aphids and mites increase on many crops as warm and dry conditions return.
According to Michigan State University Extension via Enviro-weather, temperatures for the week at the Southwest Michigan Research and Extension Center averaged near normal with highs from 68 to 86 degrees Fahrenheit (average is 79) and lows from 45 to 61 F (average is 57). The area received no rain during the period. Unlike much of the rest of the state, we are behind in seasonal rainfall by almost 6 inches and non-irrigated fields are showing areas of stress.
Recent dry, warmer weather has helped to increase mites and aphids, especially in peppers, vine crops and tomatoes. Incidence of viral diseases and powdery mildew is also increasing on vine crops. Powdery mildew leads to decline of older leaves and growers should make an effort to maintain those leaves, at least on pumpkins, until mid-September. Early leaf loss can lead to sunscald and fruit decline. Several products are effective in controlling powdery mildew. Make sure to rotate products to minimize the chances of developing resistance.
Sunscald is developing in peppers. This often happens after first harvest since harvest activity opens up plants and exposes the remaining fruit. I have also received several comments, and personal observations, that pepper plants have not grown as full as they normally do, especially for those planted around May 20. The only thing I can contribute it to is that those plants experienced a period of cool (four nights in the 30s), wet weather shortly after planting and had a difficult time recovering.