Insect pests of vegetable brassicas in Western Australia

Apple weevil and whitefringed weevil larvae

Pre-crop soil sampling: sample soil in a grid pattern across the paddock to be cropped. Check for weevil grubs and African black beetle adults.

Control methods for these pests are not registered, but are the subject of minor use permit applications. Check on the status of the permits for availability of these uses.

Vegetable beetle larvae and adults

Pre-crop sampling: based on a control method which is the subject of a minor use permit application. Check on the status of the permit for availability of this use.

Control methods for these pests are not registered, but are the subject of minor use permit applications. Check on the status of the permits for availability of these uses.

African black beetle adults

Pre-crop soil sampling: sample soil in a grid pattern across the paddock to be cropped. Check for weevil grubs and African black beetle adults.

Control methods for these pests are not registered, but are the subject of minor use permit applications. Check on the status of the permits for availability of these uses.

Slugs and snails

Pre-crop soil sampling and use of snail and slug pellets: by placing mounds of bait across a paddock, the presence of snails and slugs can be assessed. If required, the bait can be broadcast across a paddock before or just after seeding/transplanting as a control method.

Broadcast pellets before or after seeding or transplanting.

Apple weevil adults, vegetable weevil larvae and adults,
small lucerne weevil adults, spotted vegetable weevil adults, cutworm larvae

Wilting or dead plants or leaf damage to young plants and insect presence: these pests can cause young plants to wilt or die. Some of these insects feed only at night so to identify the pest involved daylight examination will require checking the soil or under clods or debris near affected plants.

Insecticides for some of these pests are the subject of minor use permit applications. Check on the status of permits for availability of these uses.

Diamondback moth adults

Pheromone trap: install a pheromone trap after periods of no pest activity such as winter to indicate arrival of moths and need to commence intensive crop monitoring for damaging larvae. Only one trap per crop is required. Install the trap near the edge of a crop and at crop height.

Do not target moths – spray grubs.

Diamondback moth larvae

Whole plant sampling, based on recommended thresholds: check whole plants for presence of diamondback moth larvae. Use the most up to date crop scouting (monitoring) chart for advice on number of plants to check and spray threshholds. Because food for diamondback moth larvae is restricted to brassicas, reduce the chance of pest carry-over to adjacent plantings by destroying crop residues as soon as possible after harvest. Use the insecticide Resistance Management Strategy to delay onset of resistance.

Spray the crop, observing the resistance management strategy guidelines, using diamondback moth-registered insecticides.
Destroy crop residue after harvest.

Cabbage white butterfly, cabbage aphids and green peach aphids,
cabbage centre grub larvae, heliothis larvae, vegetable looper larvae

Whole plant sampling: check whole plants for presence of these pests or signs of their feeding - leaf damage, faeces on leaves. These pests are less likely to be important when crops are being sprayed to control diamondback moth larvae. Check for them in the same manner and same time as checking for diamondback moth larvae. Reduce  chance of pest carry-over to adjacent plantings by destroying crop residues as soon as possible after harvest.

Spray the crop, observing the resistance management strategy guidelines, using registered insecticides. Destroy crop residue after harvest.

Slugs and snails, onion maggots, staphylinid beetles

Check curds for maggots and damage: check curds for presence of these pests or signs of their feeding — channels and discolouration on curds, and for slugs, damage to leaves. For slugs and snails, pre-crop sampling is important to implement early, effective and preventive control. For onion maggot, preventing damage based on pest presence is almost impossible as damage is usually noticed before the pest is detected. There are no monitoring techniques available for adult flies, so preventive control is not possible. Be aware of curd damage by maggots and staphylinid beetles and apply insecticides as soon as possible to avoid further damage. Reduce the chance of pest carry-over to adjacent plantings by destroying crop residues as soon as possible after harvest.

Spray the crop, using registered insecticides.
Destroy crop residue after harvest.