|Crop Knowledge Master|
Apomecyna saltator (Fabricius)
Jayma L. Matin Kessing, Educational Specialist
Ronald F.L. Mau, Extension Entomologist
Department of Entomology
Updated by: J.M. Diez April 2007
The grubs of this beetle tunnel in the vines and stems of many cucurbit plants. They are infrequent pests of cucumbers, pumpkins, squashes, watermelons, and gourds (Fullaway and Krauss, 1945).
An extensive distribution of this beetle was not found in the literature; however, papers reviewed indicated its presence in Australia (May, 1946), Hawaii and India (Samalo and Parida, 1983; Samalo, 1985). This beetle was first reported in the state on Oahu in 1896 and has been reported on Hawaii, Kauai and Maui.
Grubs bore into the main vines of plants, and produce a swelling of the stem. The feeding tunnel is usually directed towards nodes and is filled with glutinous waste material (May, 1946).Other than scar tissue at the site where the larvae entered the stem, infested plants usually show no conspicuous symptoms (May, 1946). Under very severe infestations young plants may die, but older plants often live to produce fruit at reduced yields (May, 1946).
The developmental biology of this beetle is not well studied and the duration of each life stage is not know. Another borer in the same genus, Apomecyna neglecta (Pasc.), had the following developmental periods in a laboratory study at 84.2û F (29û C): eggs hatched in 5 - 7 days; the six larval stages were completed in 31 - 37 days (the first five stages were 3-5 days each and the last 14-15 days); the pupae had a 2 -3 day prepupal period followed by 7 - 9 days of pupation; and the adults lived for 37 - 41 days (Shah and Vora, 1974). The cucurbit longicorn may have a similar development. May (1946) reports that there may be two or three generations of this insect per year in melons in Queensland, Australia which is slightly warmer than Hawaii.
The whitish-yellow, oval eggs are laid in holes at the nodal joints of vines. Sap often oozes from these holes and closes up the opening. These areas swell then later split open on squash vines (Samalo and Parida, 1983).
The grubs are cream colored and about half an inch long when full grown (May, 1946).
The grubs pupate within a fibrous cocoon they construct within the stem (May, 1946).
The slate-gray beetle is about a half an inch long with several white spots arranged in three evenly shaped V markings across the wing covers of the insect (May, 1946). Like other beetles belonging to the Cerambycidae family, the cucurbit longicorn has very long antennae (about two-thirds the length of the body).
Seedlings should be carefully examined for grubs and adults in the roots and shoots to avoid the planting of infested material (Samalo, 1985). Care must be taken to use practices that assure that plants will grow vigorously. The remains of harvested plants should be destroyed immediately after harvest to prevent larvae and pupae from starting new infestations.
Many insecticides provide satisfactory control. Studies done elsewhere suggest that endosulfan, chlorpyrifos and fenvalerate gave 70 - 85 percent control. Malathion and Carbaryl provided lower rates of control (Samalo, 1985).
There is no listing for endosulfan as of April 2007.
May, A. W. S. Pests of Cucurbit Crops. Queensland Agricultural J. 62(3): 137-150.
Samalo, A. P. and P. B. Parida. 1983. Influence of Spacing and Levels of Nitrogen on Vine-Borer Incidence and Yield of Pointed-Gourd. Indian J. Agric. Sci. 53(7): 574-577.
Samalo, A. P. 1985. Chemical Control of Pointed Gourd Vine Borer, (Apomecyna saltator) Fabr. Madras Agric. J. 72(6): 325-329.
Shah, A. H. and V. J. Vora. 1974. Biology of the Pointed Gourd Vine Borer, Apomecyna neglecta Pasc. (Cerambycidae: Coleoptera) in South Gujarat. Indian J. Ent. 36(4): 308-311.