This article was published originally on 5/30/2012
The following are highlights and updates about samples and questions recently received in the Plant & Insect Diagnostic Clinic:
Enough growing degree days have accumulated in Iowa for emerald ash borer adult beetles to have begun initial emergence if they are present. Southern Iowa has enough accumulated heat units to be at peak adult beetle activity. Now is the time to be looking for adult beetles and now is the time to review how to recognize EAB beetles and other similar-looking insects! Remember there are a lot of iridescent insects out there - the six-spotted tiger beetle is our most common sample of similar looking insects.
Spiders, spiders and more spiders. Most of the spiders we have identified have been wolf or fisher spiders and both are harmless. In Iowa, the brown recluse is the only poisonous spider and it is very uncommon.
Lots of tomato plants coming into the clinic. This week we diagnosed bacterial canker on some tomato plants.
We isolated oak wilt from a sample. Oak wilt is a serious disease of oak. Please contact us if you would like a tree tested for oak wilt for specific instructions on how to collect and mail the sample.
Ascochyta has begun appearing on lawns. This disease can cause a lawn to brown almost overnight, but luckily most turf will recover. See this iaTURF blog post from last year for more information on this disease.