Plum Curculio

Getting to Know Him

This little guy is about 3/16 inch small and looks a lot like the bean weevil that you may well know. He leaves the ugly scars on fruit, that look like a smile with a scar, called cat face. If the larvae hatch then there are worms inside. The plum curculio hibernates in the leaves and debris underneath the tree, as well as the bark and in the grass and forest near by.

He attacks stone fruit mainly. His preferences are peaches, plums, cherries, apples, blueberries, cherries, nectarines and other such fruits.

When the temperatures reach 70 degrees for two consecutive days, the plum curculio starts to wake up and become active.  This happens around February or March in our part of Texas. You know what happens when you wake up after a long sleep don’t you?  You are hungry! If the daytime temperatures haven’t been warm enough he crawls to the tree to start feeding. If they are warmer he flies.   The plum curculio adult does not start to damage fruit until the night time temperatures reach 60 degrees.

When Do I Plan My Attack? When 75% of the flower petals fall spray your fruit trees with an approved insecticide such as  pyrethrin.  To control adults it is critical to time your applications at the petal‑fall and/or first-cover stage for apples, and the shuck-split and first-cover stages in peaches and cherries.  By controlling the adults you will control them from laying any eggs.  You also want to repeat applications at 10 to 14 day intervals until the population is controlled.

Methods for Monitoring

The reason for monitoring is to see how bad of an infestation you have. Spraying should take place if you have a 1% infestation or loss of fruit. The methods of monitoring are as follows.

Pyramidal Weevil Trap – This is a synthetic lure that is placed on top of a good sized wooden pyramid.

Jarring Trees – Jar trees over a sheet or a beating tray early in the morning. It must be done early in the morning as the plum curculio will be less active and easier to be dislodged.

It is important to cultivate a few inches deep around the base of the trees as to dislodge and disrupt the plum curculio in the spring.

Approved  Biorationationals

Azadirachtin – This product is made from the seeds of the neem tree.

Beauveria bassiana This is a naturally occurring fungus.

Kaolin This is a particle film barrier and there has been great success with apples using kaolin.

Pyrethrins Are made from a crushed chrysanthemum flower.  Be sure to spray early in the morning.

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