Timing of release
Trichogramma should be released when moths are active and laying eggs. Refer to your local history for a guide when ordering. Peak egg lay usually occurs just after a peak in the number of moths caught in pheromone traps. Heliothis or looper eggs are easily seen in most crops. They are about 1 mm in diameter and creamy white, usually laid on the tops of young leaves or near flowers.
Sixty capsules per hectare each containing 1,000 wasps is the base rate. This rate should be increased or decreased depending on pest pressure. It is best to make two releases, a week apart. This will lengthen the period of the wasps activity and will provide a more even emergence of the offspring from parasitised eggs. If regular scouting and parasitism checks are done through the season and these reveal moderate to high levels of parasitism then future releases may be reduced or even omitted. (see "Monitoring Egg Parasitism" data sheet for details).
The capsules provide a convenient method of distributing Trichogramma. They are useful in areas where showers are common or where the parasitised eggs need protection from predators in the crop. Each capsule contains a minimum of 1,000 parasitised moth eggs. The wasps will begin to emerge around the time stated on the package if kept at the temperature noted. If it's cooler, they will take longer to emerge and if warmer, will emerge more quickly.
The package will also be accompanied by a small clear vial containing parasitised eggs. This vial is used as an indicator of wasp emergence. The wasps in the clear vial will emerge about 24 hours before those in the capsules. So start placing the capsules in the field when the wasps emerge in the clear indicator vial.
Delaying Wasp Emergence
If field conditions are unsuitable for release (raining or very hot), the capsules and indicator vial can be stored in a standard fridge for up to 3 days. Do not allow the fridge to drop below 3ûC.
Placement of Trichogramma release capsules in vegetables
Staple the capsule through one corner to a leaf or post (tomatoes) or drop them into a whorl in sweet corn. In cotton and soybeans capsules can be placed in the shade under the plants.
If it's hot select a shady spot. The wasps will gradually move down wind so place any extra capsules along the windward boundary of the crop. Use the Table to find the distance between capsules.
For example, when applying 90 capsules per hectare, place the capsules in a grid approximately 11 m by 11 m.
Inoculative releases into field crops
For low rate releases into larger areas (cotton, maize, sorghum, soybeans) the capsules can be placed in bands rather than a strict square grid. This cuts application time down considerably.
for 60 caps/ha, place a capule every 8 meters in bands 20 meters apart.
for 30 caps/ha, place a capsule every 13 m in bands 25 m apart
for 15 caps/ha place a capsule every 13 m in bands 50 m apart