July 11, 2007

Plant and Insect Diagnostic Clinic Update - July 11, 2007


Samples with the following problems have been seen in the Clinic recently:


Anthracnose on maple

Ash rust

Diplodia canker on concolor fir

Strawberry Root Weevil: July's Accidental Invader


The strawberry root weevil is a very common insect found throughout Iowa. The shiny black, hard-shelled adult weevils are about one-third inch long. They have a pear- or light bulb-shaped body and long elbowed antennae. The wing covers are marked by many rows of small pits.

Strawberry root weevils emerge from the soil in mid-summer (July) after spending the past 11 months in the soil as larvae feeding on the roots of strawberry plants, evergreen trees and other plants. Root feeding by larvae is generally not significant as is the foliage feeding done by the adults

Japanese Beetles are Active Now


The Japanese beetle discussed in an earlier newsletter has emerged and is causing foliage and flower feeding injury in the isolated areas of the state where this introduced pest is found.

Physiological Disorders of Tomatoes


While tomatoes are easy to grow, insects and diseases can damage plants and reduce crop yields. Environmental stresses can cause additional problems. Physiological disorders of tomatoes include blossom end rot, fruit cracking, and sunscald.

Blossom end rot is a common problem on tomatoes. It appears as a brownish black spot on the blossom end (bottom) of the fruit. Secondary organisms invade the brownish black spot and cause the fruit to rot. Blossom end rot is most common on the earliest maturing fruit that ripen in July and early August.

Root and butt rots of hardwood trees


This week's topic is of a rather delicate nature but nevertheless must be dealt with as promised in a previous HHPN article. Does your tree suffer from butt rot? Don't be embarrassed if you can't answer because this disease often takes place under our noses for years without our knowledge. It may eventually manifest itself in the form of shelf or bracket fruiting bodies or mushrooms.