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item1 Trissolcus egg parasitoid of green item1
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Background

Trissolcus is a small black wasp about 2 mm long. Its an egg parasitoid of green vegetable bug and a range of other bugs including Small Green Stink Bug, a significant pest in raspberries. The female wasp uses the bug eggs to rear their own young. It is commonly found in crops all over Australia

Under the right conditions, they can make a major contribution to the control of this important pest. They are typically in low numbers coming out of winter and then spraying in crops prevents them from getting to significant levels.

Green Vegetable Bugs

GVB is a major pest in many crops including soybeans, cotton, sweetcorn, macadamia nuts, (in some areas), pecans and tomatoes. Green stink bug is a significant pest in raspberries.

GVB breed within many crops but adults typically fly in from neighbouring crops and get things going.

District wide benefits?

Recent experience with Trichogramma wasps against macadamia nutborer has shown that area wide benefits can be achieved from mass releases of parasitoids, not just the short term impact with in the crop. This is likely to be the case for other parasitoids like Anastatus and Trissoculs and Trichopoda.

High levels of parasitism from local parasitoids have been observed latter in the season. This suggests the wasps are very capable given the right conditions.

By making mass releases this should be more common and help to reduce overwintering bug populations. The more farms in an area making releases the more likely this is to happen.

Selecting sites suitable for Trissolcus release

  • GVB or SGSB typically a problem most years
  • Crops where adult bugs are breeding within the crop and laying eggs and producing nymphs.
  • Identifiable likely source/s of bugs adjacent to crop an advantage
  • Records of past damage levels at harvest for comparison
  • Previous records observations of bugs numbers if available
  • A preparedness to not spray, or just spot spray if presence of bugs was deemed low

For more info on green vegie bugs see the Qld DAF Info Sheet at:

https://www.daf.qld.gov.au/plants/fruit-and-vegetables/a-z-list-of-horticultural-insect-pests/green-vegetable-bug

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GVB eggs are laid in tight clusters of near 100 eggs.

GVB hatchlings

GVB 3 weeks old

if the food is good a GVB female laying a raft of eggs.