August 26, 1992

Why are the Trees Losing their Leaves?

All over Iowa, it seems that some deciduous trees are celebrating fall about two months early. Since early August, premature fall coloration, browning of leaves, and heavy defoliation have been common on hackberry, oak, ash, and sycamore, among others. What's going on? Early senescence is usually a response to stress; 1988, the worst drought year, was the last time many species of trees lost their leaves so early. In 1992, the likely culprit is residual effects of the November 1991 freeze.

Maple Aphids

[Production Note: open with music: 'The falling leaves . . . .'] Aphids are doing very well this summer, in spite of the wet rainy weather in July. Greenbug aphid on turfgrass was the first and most noticeable, while others developed less obviously.


The month of August normally brings with it a rash of phone calls and inquiries regarding flea control. This year is no exception. While we typically talk about late summer as being "flea season", in reality the fleas have been with us throughout the spring and summer. By this time of year, however, their populations have increased to the point that they cannot be ignored or overlooked.

Think Spring this Fall -- Plant Flowering Bulbs

I believe garden flowers are most appreciated and enjoyed in early spring. They are a refreshing change from the drab browns of winter. Unfortunately, we have to plan and plant for this beauty several months before we actually see the end result. Fall is the time of year to plant spring-flowering bulbs for that early splash of color in your garden and landscape.

Annual White Grub Prediction

An article in the July 29, 1992, issue of the Horticulture and Home Pest Newsletter explained the background biology and management options for this common and widespread pest of turfgrass. The action threshold, that is, the number of grubs needed to justify insecticide treatment is 10 or more grubs per square foot in healthy turf. It appears most grass is in good health for this time of year because of the abundant rainfall and the higher threshold is still suggested for most lawns.

Fall Lawn Weed Control

Even though the cool weather in July and August has been a curse for farmers, it has been a blessing for anyone with a cool-season lawn. The rain and cool temperature has caused many homeowners to mow their lawn almost twice a week versus only twice for the entire months of July and August last year. The lush green lawn is a homeowner's paradise and it didn't even cost a huge water bill. However, after a closer look, one also notices that it was a very good year for a lot of weeds.