Archive for Wednesday, July 9, 2008

Now’s time to spray for squash bugs, bagworms, grubs

July 9, 2008

I hope everyone made it through the long holiday weekend at least mostly unscathed. Now it's time to forget about food and fireworks and concentrate again on the lawn. We're well into the month of July, so there are many hot yard and garden topics to talk about besides the effects of a smoke bomb on the lawn! The new tasks at hand are to get ready to spray for some of our old insect friends (bagworms, squash bugs, and grubs) and also to be on the lookout for brown patch in tall fescue lawns.

I'll start off talking about bagworms. All of the bagworm eggs have hatched by now and the small larvae are crawling around eating. This means it is time to spray them. The larvae at this stage are most vulnerable to insecticide, and are doing the least amount of damage, so spraying now is very important. Just about any insecticide that is labeled for bagworms will work. Rather than worry about which chemical to use, make sure to get the chemical diluted with the correct amount of water, if necessary. Also be sure to thoroughly cover the tree with spray so you don't have untreated areas where some larvae can survive.

Another troublesome insect to start spraying for now are squash bugs. The insects are grey, shield-shaped members of the insect order Hemiptera that like to feed on squash, pumpkins and melons. The first young squash bugs are now hatching, so it is time to spray! Like bagworms, they are much easier to kill when young, so timing is important. Control of this year's first batch of squash bugs is crucial because the young ones that are out now, if left alone, will eventually lay the eggs that will become adults later in the summer and cause even more destruction. Squash bugs feed on the plants by sucking juices from them, rather than chewing on them like other insects, so contact insecticides are the most effective way to kill them. The best insecticides to use are permethrin, malathion, rotenone, and methoxychlor. The insects are on the underside of the leaves, so it is important to spray the bottoms of the leaves with these chemicals.

I'd also like to remind everyone that it's time to put down grub control products. Grub "preventative" products that contain Merit or Mach 2 should be put down on the lawn now so they are in place when the new grubs hatch and begin feeding. By having the product in place now, they will kill the new grubs before they start damaging your lawn. Traditional grub treatments such as Dylox are usually applied later in July, when the grubs are already present, but those types of products are not as safe for children and pets to be around as the products with Merit and Mach 2. Merit is the chemical in "Bayer Season-Long Grub Control" and in "Grub-Ex", while "Kill-a-Grub" contains Mach 2. All of these products need to be watered in soon after application for best results.

I will briefly mention brown patch in fescue lawns, which has been reported in Manhattan already this summer. Brown patch is a fungal disease that affects tall fescue, perennial ryegrass and creeping bentgrass. It causes brown patches in grass during hot, humid weather. The fungicide chlorothalonil can be used either on monthly intervals through May, June and July for preventative purposes, or be used soon after an infection is noticed to suppress the disease outbreak. If you think you have brown patch, give me a call for more information, or check out the K-State brown patch publication online at oznet.

If you have questions , stop by the K-State Research and Extension Office at 500 Eisenhower Road, Suite 103, in Leavenworth, call me at (913) 250-2300, or send an e-mail to me at


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