Moth, leek

Leaf odours. The total essence which emanates from growing leaves is not solely constituted of straight chain alcohols and aldehydes. In the insect s selection of a host plant, species-specific components might be involved. The leek moth Acrolepiopsis assectella is attracted by thiosulfinates, compounds isolated from leek. Cis-3-hexen-1-ol was also shown to be attractive (27). 

Several species of insects are associated with Allium species. For example, both adults and larvae of Delia antiqua, the onion fly, are atb-acted to disulfides characteristic of these plants (Stadler, 1992). Another specialist, the leek moth, Acrolepiopsis assectella, was found to respond to the same group of compounds. However, dipropyl sulfinate, the precursor of the disulfides, is even more stimulatory. A parasite of the leek moth, Diadromus pulchellus (Ichneumoni-dae), reacts mainly to the disulfides that emanate from leaves damaged by the leek moth (Stadler, 1992). 

Larvae of the leek-moth, Acrolepiopsis assectella, feed on the leaves of various Allium species, but usually avoid the flowers. The saponin aginoside was isolated from these flowers and shown to be toxic to the larvae. The level of toxicity was reduced by addition of cholesterol or sitosterol to the diet of the larvae (Harmatha et al., 1987). 

Harmatha, j., B. Mauchamp, C. Arnault, and K. Slama, Identification of a spirostane-type saponin in the flowers of leek with inhibitory effects on growth of leek-moth larvae, Biochem. Syst. Ecol., 15, 113-116 (1987). 

Acanthoscelides obtectus Bean weevil Coleoptera Bruchidae Acrolepiopsis assectella Leek moth... 

Cutworms, bean seed fly, onion fly, leek moth and thrips can be a problem in the crop. Rust, foot rot, leaf blotch, white tip and white rot are the main disease problems in leeks. 

Caterpillars of this moth tunnel into the leaves of leeks. The damage is worse in warm, dry summers. The adult moths spend the winter in plant debris. There can be several generations in a year. 

What to do Where this pest is a regular problem, grow leeks under fine mesh netting to keep the moths out Once plants are infested, there is no control other than hand-picking of caterpillars and cocoons from the leaves, or removing the whole plant Clear up all plant debris at harvest Dig over the leek beds. Encourage predators... 

Fipronil s high intrinsic activity against Dipterans allows its successful use as a seed treatment in several crops for control of root maggots. In cereals, fipronil provides excellent control of wireworm and wheat bulb fly (Delia coarctata) at rates of 50 g per 100-kg seed [8]. In leeks, seeds filmDelia antiqua) as well as thrips and onion moth [106, 107]. 

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