Ask the determined gardener: Armyworms

How can I eliminate armyworms?

Armyworm populations are more of a nuisance than a cause of serious lawn damage, but can sometimes need control. They can measure up to 1.5” long. Their larval stage can last several months and can live both underground and aboveground.

You can monitor armyworm populations with a solution of 2 Tablespoons of lemon scented dish detergent in one gallon of water. Splash this on the area and watch what emerges. If you see two to three small caterpillars in a 1 square foot area, treat the area. A product containing Bt (Bacillus Thuringiensis), which is an organic powder, can be sprinkled to treat for these pests.

There are also other products that are labelled as treatments. Be sure to read and follow all instructions. For more information on other lawn pests and treatments see Oklahoma State University publication EPP-7306.

Many of my pecans are dropping early

Heavy rains in August can cause water stage fruit split, or water-split. Water-split can be a problem with many thin-shelled varieties and to a lesser degree some thick-shelled varieties.

Water-split is highly erratic, with incidence and severity varying by cultivar, location and year. This occurs in the “late water stage”, when the kernel is rapidly increasing in volume as the shell is hardening. Many times you will see an abundance of nuts on the ground, some with the shell only split (light green husks which will stain a few days’ afterword, or with violent cases where the shell and husk are both split).

Managing soil moisture and minimizing water stress during the last 2 weeks of fruit sizing, and crop load thinning can lessen loss. To learn more, search “pecan water-split extension” to get university based publications on this subject.

I am seeing creepy green June beetles everywhere

Green June Beetles (Cotinis nitida) are larger and more robust than their smaller relative, the common brown May/June Beetle, measuring from ¾ to 1-inch long. The color varies from dull brown with green stripes.

These beetles injure many fruits such as grapes, peaches, blackberries, apples, plums and apricots to name a few. They frequently feed on the sap of oak, maple, and other trees and on growing ears of corn. The larvae feed on decaying organic matter or well-rotted manure or compost piles. Ripening fruits are damaged by the feeding of adult beetles. Their odor and excrement ruin most pieces of fruit they visit even if the feeding damage is not severe.

This insect overwinters as a nearly mature larva in the soil, feeding and maturing in late spring, pupating in the cell then emerging beginning late May or early June. They are active through early October in some years. Green June Beetle grubs come out at night, crawling on their backs from one place to another. Watch for birds feeding on turf areas, especially starling and robins: this is a good indicator of grub activity.

Grub treatments may be the best control. Grub control works best during August through October. Early spring treatments are not as effective. Products labeled for grub control are most effective. Apply late in the day because grubs come out at night and are then exposed to the chemicals.

Keep a history of affected areas on a landscape map to better target new infestations. Products containing Cyfluthrin, Cypermethtrin, Esfenvalerate (Ortho Bug-Be-Gone Max Garden & Landscape Insect Killer), or Nosema locustae are effective treatments. Treatments may be best targeted around the base of trees. Again, follow guidelines for treatment around fruit and nut crops.