How to Get Rid of Vine Borers

Once squash vine borers are inside the plant, they are difficult to treat. Often, symptoms like wilting come on quickly, so borers are not caught until it is too late. Adult borers are moths that look more like wasps with an orange and black body and metallic green front wings. The real trouble with borers is not the adults, but the larvae. Shortly after hatching from their eggs, the larvae tunnel into stems for weeks. Their tunnels cut off the water supply to the plant, which eventually kills it. Although borers are certainly hard to treat, it is not impossible to get rid of them.

Yellow pans or bowls filled with water
Ready-to-use insecticide containing the active ingredient carbaryl, permethrin, bifenthrin or esfenvalerate
Sharp knife

Instructions

- 1
  Put yellow pans or bowls filled with water around or above the plant. Adult borers are attracted to yellow, so they will fly into the pan and become trapped. Place traps throughout the summer, when the adult borers become active. Check and empty the traps daily.
- 2
  Examine the base of the stem, leafstalks and undersides of the leaves for eggs. Borer eggs are about the size of a pencil point, dark reddish-brown and slightly flat. Crush the eggs between your thumb and index or middle finger.
- 3
  Spray the bases, crowns and runners of the plants with a ready-to-use insecticide containing the active ingredient carbaryl, permethrin, bifenthrin or esfenvalerate. Apply the insecticide with high pressure to create a mist beneath the canopy of the plant. The best time to start applying insecticides is in the evening when vines begin to run or when adult borers are first detected. Repeat applications every seven to 10 days for two to five weeks.
- 4
  Examine the stems for borer entry holes just above ground level in the early summer. The holes may be filled with moist orange or green sawdust-like material, commonly called frass. If the stem has holes in it, it is infested with larvae.
- 5
  Slit the stem vertically with a sharp knife, avoiding slitting it more than needed. Remove larvae from the stem. Larvae are thick, white with brown heads and about 1 inch long. There may be several larvae in each stem, but normally there is only one larvae. Mound moist soil a few centimeters above the wounded stem.
- 6
  Destroy plants immediately after harvest to prevent larvae from continuing their development. Pull any plants killed by borers immediately.

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