|scientific name Diadegma |
Cruciferous crops and herbaceous plants.
Number of Diadegma generations per year, corresponding to the number of its host generations (Edward 1997).
Many misidentifications have been disseminated in the literature of this genus due to the variable characters of subfamily Campopleginae. However, the identification is mainly based on morphological characters, such as dorsal view of head or propodium. (Azidah et al. 2000; Fitton and Walker 1992).
Adults are very small ranging from 6mm to 1cm. Body rather short and stout to very long and slender. Clypeus of moderate size and convex. Mandible of medium length with a lower tooth smaller or equal to upper tooth. Propodium short or very long with obsolescent carinae and rounded spiracles. Fore wing 2.5 to 9 mm long.Tarsal claws are usually pectinate, short to moderately long. Hind tibia coloured or darkened at apex. First abdominal segment is short and stout or long and slender. Ovipositor usually long but sometimes stout and up curved (Townes 1969).
The total development period of Diadegma under temperate conditions from egg to adult is about 14-21 days. The adult female of Diadegma laid its eggs inside the body of the host larva. After hatching the wasp larva eats the contents of the host larva and spins its own cocoon inside the host. When the host larva stops feeding and starts to pupate, the Diadegma eventually kills its host. Pupa of Diadegma is dark coloured as compare to its light coloured host pupa (Philippine German Plant Protection Project, 1996).
Adult Diadegma female feeds on nectars of flowering weeds, corns, beans, tomatoes, alfalfa, pollens, honeydew of aphids and on crops where their hosts are found. The plants with wide or shallow corollas like Brassica crops, are the best nectar sources for Diadegma wasp and very important to conserve their population (Kfir 1997). Diadegma is extremely susceptible to pesticides. Therefore, it is recommended to avoid unnecessary practice of pesticides to conserve their population. (Philippine German Plant Protection Project, 1996).
Mainly Lepidoptera of small and medium sized (Townes 1969).
The genus is distributed worldwide, primarily with Nearctic, northern Neotropic and Palearctic range. (Fitton and Walker 1992).
Many species of Diadegma are the vital natural enemies of Diamondback moth, can parasitize up to 90% of their larvae. Some species have short and some have long ovipositor so they can easily parasitize both hidden and exposed larvae of their host (Philippine German Plant Protection Project, 1996).
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