No gardener wants to see their pecan nut crop diminished thanks to a handful of bothersome insects, even if this represents nature taking its course. Whether the garden contains one tree or an entire grove, a number of insects may attack a pecan tree. Two of the most serious pests are pecan nut casebearer and pecan weevils. While these insects may be treated with pesticides, understanding the nature of the insect remains the first step in handling the problem.
Pecan Nut Casebearer
The casebearer is a moth that lays eggs four times each year. The most damaging event is when the casebearer moths lay their eggs the branches right before pollination. Once the eggs hatch, the larvae tunnel into the nuts, completely destroying the fruit. The white eggs may be seen with the naked eye, especially as the eggs start to show red spots right before hatching.
Weevils are hard-shelled beetles that emerge from the soil in late July and August. The weevil enters the nuts, causing them to stop maturing and completely ruining the pecan. To make matters worse, the female weevil lays eggs in the pecan kernel. The larvae then feed on the nut, eating the whole kernel. Once the larvae leave the shell, they drop to the ground and burrow into the soil. While they stay in the soil for two to three years, they eventually return and the damaging cycle starts again.
Resembling bagworms, fall webworms are caterpillars capable of defoliating entire trees. The first sign of this insect consists of one to two-yard long thick, white webs that cover a cluster of leaves. These webs house the caterpillars with the leaves providing food. Each worm leaves the web in late fall to construct and live in a hairy cocoon under the pecan tree's bark. The larvae turn into gorgeous white moths in early summer just in time to start the cycle all over again.
In early August, stink bugs start appearing on pecan tree leaves. The bugs head to the trees after spending the summer feeding on other plants, especially soybeans. The bugs may feed on nuts with soft shells, causing the fruit to stop growing. If the bugs feed on hardened shells, the shells sport large black spots. Although the nuts are still edible, they don't look very attractive; in commercial markets, these pecans would be considered inferior, resulting in a lower price.