July 25, 1997

Downy spot - Hickory

A hickory sample showing signs of downy leaf spot was recently submitted to the Plant Disease Clinic. The sample was collected in Dubuque county. Downy leaf spot, also referred to as white mold or white leaf spot, is caused by the fungus Microstroma juglandis. Downy leaf spot affects various species of walnut and hickory.

Proper Mowing Practices During the Summer Months

Sound mowing practices are necessary to obtain a good quality lawn. This is especially true during the summer months. Improper mowing practices during periods of drought and high temperatures may seriously damage turfgrass.

Spider Mites on Vegetable and Landscape Plants

A hot, dry summer like has been occurring in many parts of Iowa could mean spider mite problems for many of our landscape and garden plants. Spider mites feed externally on the foliage of nearly all vegetables, flowers, trees and shrubs. They use piercing-sucking mouthparts to puncture the plant tissue and feed on the liquid within the cells. In light infestations the foliage will appear to be speckled with very tiny yellowish-green spots. If the population of mites increases the damage can become severe enough to turn the foliage entirely greenish-yellow and eventually tan or brown.

Strawberry Root Weevils -- They're Back!

That familiar sight of summer, the strawberry root weevil, is here again. The Strawberry Root Weevil is a small, hard-shelled, shiny black beetle with a narrow head and thorax and large, round abdomen. An easy way to describe them is "light bulb shaped." A common concern is that this household accidental invader is a tick. Unlike ticks, the Strawberry Root Weevil has 6 legs and a pair of rather long, elbowed antennae.