The squash vine borer (''Melittia cucurbitae'') is a diurnal species of sesiid moth. The moth is often mistaken for a

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyly, monophyletic lineage within the ...

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. Th ...

because of its movements, and the bright orange hind leg scales. The females typically lay their eggs at the base of leaf stalks, and the caterpillars develop and feed inside the stalk, eventually killing the leaf. They soon migrate to the main stem, and with enough feeding damage to the stem, the entire plant may die. For this reason, it is considered a pest that attacks cultivated varieties of

squash Squash may refer to: Sports * Squash (sport), the high-speed racquet sport also known as squash racquets * Squash (professional wrestling), an extremely one-sided match in professional wrestling * Squash tennis, a game similar to squash but pla ...

, zucchini, pumpkin, and acorn squash. The squash vine borer is native to North America, with some reports as far south as Brazil and Argentina. It lives in most temperate North American states, except the

Pacific coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas Countries on the western side of the Americas have a Pacific coast as their western or southwestern border, except for Panama, where the Pac ...

. Southern states have two broods a year.

Control

Pesticides are ineffective after the larvae are inside the plant. Gardeners find this a difficult pest to combat. Some try to avoid the pest by timing the production season to harvest before the pests can build up, or after they have peaked. Prevention includes pesticides to kill the adult moth (such use must not contaminate the flowers, as

pollinator A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are the maj ...

s would be killed by poisoned

nectar Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

). Preventing it is difficult. One way is to extract the caterpillar from the stem of the plant. The following organic methods of control are quite manual and may only apply to small-scale or home gardeners. BT (bacillus thuringiensis) bacteria may be injected into the base of the stem using a syringe, to attempt to kill the larvae, ideally while still small. It should be done sometime after the first flowers start to show and possibly again after a few weeks. A small utility knife and tweezers, or other fine tools, may be used to gently cut open the stem and try to extract the larva. Look for a hole in the stem with frass coming out of it. The larva is usually several inches above that point. If this is done in a gentle enough way, and before the moth has caused extensive damage, the exposed stem may be covered with soil, allowing the plant to re-establish roots higher up on the stem, and the plant may be saved.

Habitat

Organic controls include wrapping the lower stem with

nylon stockings Stockings (also known as hose, especially in a historical context) are close-fitting, variously elastic garments covering the leg from the foot up to the knee or possibly part or all of the thigh. Stockings vary in color, design, and transparen ...

aluminum foil Aluminium foil (or aluminum foil in North American English; often informally called tin foil) is aluminium prepared in thin metal leaves with a thickness less than ; thinner gauges down to are also commonly used. Standard household foil is typ ...

to prevent egg laying, which generally occurs within a couple of inches from the point where the stem emerges from the soil. Row covers can be used up until bloom. An old gardener trick for vining squash and pumpkin

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture, ...

s is to cover the vine with earth at various points along its length, inducing rooting at several points, thereby continuing to feed the developing fruit despite the loss of the original stem. However, this only works with the species ''

Cucurbita moschata ''Cucurbita moschata'' is a species originating in either Central America or northern South America. It includes cultivars known as squash or pumpkin. ''C. moschata'' cultivars are generally more tolerant of hot, humid weather than cultivars of ' ...

''. After the vine has taken root at multiple points, the infected portion of the plant can be cut off, along with another inch where the larva is eating into healthy tissue, without significant damage to the plant. Some gardeners choose to place a yellow bowl filled with water to attract and drown the adult pest, a method which provides feedback on the current level of infestation. This method, along with daily checking the plants for eggs, is popular with organic gardeners. Once larvae are present within the stems, control must be quick. Often, the first noticed sign of the infestation is wilting of the vine, and it is too late for control efforts at that point. Experienced gardeners watch the stems for signs of

frass Frass refers loosely to the more or less solid excreta of insects, and to certain other related matter. Definition and etymology ''Frass'' is an informal term and accordingly it is variously used and variously defined. It is derived from the ...

protruding from small holes, which is an indicator of the presence of the larva inside. Some gardeners carefully cut the stem along its axis and remove the caterpillar before it ruins the vine. Others use a stiff wire, a needle, or a toothpick to kill the borer without seriously injuring the vine.

Gallery

File:Frass 1310.JPG, Often,

on the stem of a squash plant is the first symptom of infestation. The second symptom follows soon - the death of the plant. File:Squash borer 1741.jpg, Zucchini squash plant stem cut open to show borers File:Melittia_cucurbitae.jpg, Life cycle File:Melittia_cucurbitae_larva.jpg, Larva File:Melittia_cucurbitae_damage.jpg, Damage File:SquashVineBorer LarvalPhase ZuchiniPlant.jpg, Another detail shot of borer in a zucchini stem File:Melittia cucurbitae P1440822a.jpg , Adult File:Melittia cucurbitae P1440819a.jpg , Adult File:20200melittia.jpg , Melittia cucurbitae

References

{{DEFAULTSORT:Squash Vine Borer Sesiidae Agricultural pest insects Moths described in 1828