UF/IFAS Vegetable Arthropod Pest Photographs CD-ROM III

Squash Vine Borer, Melittia cucubitae
(Lepidoptera: Sesiidae)

The squash vine borer is distributed throughout the United States and is also found in Central America. Natural enemies are not well studied and larvae seem to be relatively free of them. The life cycle of the squash vine borer can be completed in approximately 60 days, and there usually are two generations per year. Eggs are round and reddish-brown and can be found on the surface of plant tissue. Larvae are white with a dark brown head. The larva is marked with numerous large hairs and mature larvae burrow into the soil where pupation occurs. The pupa is mahogany brown in color. The forewings of the adult are blackish with an olive green tinge while the hind wings are colorless. The abdomen is dull orange and has black dots on the back.

Host plants that are commonly attacked include wild and cultivated species of Cucurbita. Damage is caused by the larva, which spends its entire life feeding within the plant stems. The first sign of infestation is wilting of the plant during the heat of the day while other plants remain normal in appearance. Fruit may also be infested. Population densities may be determined using sampling methods such as water traps and pheromone traps. Insecticides are commonly applied to prevent young larvae from entering into stems. Chemical control is difficult once the larva has entered the stems. Pollinators should be taken into account before insecticides are applied. Cultural control practices include trap crops and removal of crop residues.

Images

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Squash vine borer, Melittia cucurbitae, adult.
(Photographer: J. Capinera, University of Florida)
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Squash vine borer, Melittia cucurbitae, larva.
(Photographer: J. Capinera, University of Florida)
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Squash vine borer, Melittia cucurbitae, larva with damage
to stem.
(Photographer: J. Castner, University of Florida)
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