As the pecan season starts to wind down, shuck-split and harvest is starting to take place in earlier maturing cultivars. A hot summer with lack of moisture has played havoc on this seasons’ crop development, especially in native groves. While pecan weevil emergence has been light in most areas, as harvest approaches growers must still be on the lookout for stink bug and leaffooted bug activity.
Stink bug and Leaf-footed bugs are a potential problem late in the season. Although stink bugs and leaf-footed bugs don’t reproduce or develop on pecan trees, they can cause significant crop loss. Host plants can include various species of weeds, such as thistle, and cultivated crops such as cowpeas, cotton, corn, soybean, millet, grain sorghum, and alfalfa. As the season for these crops come to an end or mowing occurs prior to harvest, stink bug and leaf-footed bugs search for other food sources.
Their feeding on the nuts cause two types of damage—black pit and kernel spot. Black pit occurs with feeding prior to shell hardening, and eventual premature nut drop.
Kernel spot occurs after shell hardening and causes dark brown to black spots on the kernel surface, making this area bitter tasting. The frustrating part, if not monitoring, growers may not realize there has been damage until marketing their pecans.
Control options include elimination of weed host within and around the orchard, control of insect populations in the host crop, if possible, before they move into the orchard, and treating border areas. Utilization of insecticide for other late season pests (such as pecan weevil) can help with control.
Damage can occur past shell hardening, so continued monitoring is imperative until the crop is harvested.
Any late season applications must be made with harvest in mind. Choose insecticides carefully. Depending on the product, pre-harvest interval (PHI) can range from 7-21 days.