Biology of Bruchidius fulvus biological control agent of camelthorn weed (Alhagi camelorum) and its impact on camelthorn seed production in Birjand

Camelthorn is a perennial noxious weed belonging to the Fabaceae family that existalmost in the most regions in Iran and reproduces by seed and rhizome. In 2008, a seedbeetle was collected on legumes of camelthorn which identified as Bruchidius fulvus(Allard, 1883). Biology of this insect was studied in laboratory conditions in15±1:25±1˚C light:day, relative humidity of 65±5% and length of light: dark 12:12h andalso field (Natural) conditions. Incubation period of eggs prolonged about 6±1.71 days.Eggs placed on legumes individually and the mean number of egg lay for a female was19.8±0.95 eggs. The larva bore directly into the seeds through the cortex at the end ofembryonic development. The mature larvae change to the pupa inside the seed. Thisbeetle has 2-3 generations annually in Birjand and overwinters as larva inside extantlegumes of host plant. The larvae change to pupa and adult in late spring and earlysummer (beginning of flowering camelthorn). The adult females start to lay eggs afterhaving a taste from host leaves and flowers, simultaneous by appearing legumes. Only alarva remains inside each seed and grow after feeding from inner parts of the legumes andchange to pupa there. Adult seed beetles make their way outside by boring a small holeon the seed and extant legume. The life cycle accomplishment of this beetle from egg toadult depends on environmental condition lasted 48.8±2.48 days. Under laboratoryconditions, larval and pupal periods last about 32±0.94 and 11±0.54 days, respectively.The larvae of this beetle can damage camelthorn seeds up to 35-48% in naturalconditions. Because of its impact on seed production, the camelthorn weevil may be avaluable candidate for biological control of camelthorn in the south khorasan.