August 26, 1992
[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.
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.
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.
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.
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.
This is the time of year when populations of yellowjackets and other social wasps are large enough to be quite noticeable and when people determine 'something needs to be done.' The wasps have been present since spring, but populations were very small through the early part of the summer and didn't reach their peak numbers of approximately 5,000 yellowjackets per colony until late summer.