Grapevine Weevil is one of the hardest insects to control in the Northern Indiana/Southwest Lower Michigan area because it is an insect that is seldom seen. Grapevine Weevils are nocturnal, emerging at night and feeding on plant tissues until sunrise. During the daytime, these Weevils hide in the soil around the plant and chew on the plant’s roots. Since Grapevine Weevils are so elusive, it is difficult to tell if your plant has been infested unless you happen to notice that a large amount of the plant’s leaf tissue has been chewed away.

In late May and early June, Grapevine Weevils begin to reproduce. Their young become small white grubs that also feed on the plant’s roots. The damaged inflicted by the feeding grubs causes the needles and leaves of plants to yellow until eventually entire branches die.

Grapevine Weevils attack a large variety of plants, including Azaleas, Hollies, Rhododendrons, Japanese Yews, Weigelea, Forsythia and Barberry. In fruit and vegetable gardens, the Grapevine Weevil’s favorite food is grapes, which is how the Weevil got its name.

Constant vigilance and persistent care are needed in order to effectively control Grapevine Weevils. To kill Grapevine Weevils that have infected landscape plants, apply a systemic insecticide, such as Fertilome® Azalea/Evergreen Food Plus with Systemic or Fertilome® Tree & Shrub Systemic Insect Drench. One application of systemic insecticide is often not enough to kill all of the insects, so several applications must be given throughout the growing season to insure full control. Systemic insecticides, while highly effective long term, do not always produce instantly noticeable results, and many, in fact, take a period of days to weeks before they reach full effect. For a quicker, short term kill of the insects, treat your plants with an application of Hi-Yield 38 Plus Turf, Termite & Ornamental Insect Spray in addition to the systemic insecticide. This will kill off many of the Weevils quickly, and provide partial control until the systemic insecticide has taken effect.

Unfortunately, systemic insecticides cannot be used to treat grapevines and other edible plants that have been infested with Grapevine Weevil. For grapevines and other edible plants, use only an insecticide that has been labeled for use on fruits and vegetables. Natural Guard Neem Insect Spray RTU is an effective organic insect control for Weevils that is safe to use on edible plants. Insects do not like the taste of leaves sprayed with Neem and will not chew on them. Additionally, Natural Guard Neem Insect Spray RTU affects the larva of Weevils, preventing them from being able to molt and causing them to die.

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