General information
How does it work?
All mobile stages of Nesidiocoris tenuis are voracious predators, from the first instar to the adult.. They prey on many small invertebrates, such as whitefly and mites. Nesidiocoris also thrives on eggs of Lepidoptera, such as Tuta absoluta, and will take some nutrients from plants.
Nesidiocoris females insert eggs singly into the stems and thicker leaf-veins of plants. These eggs are extremely difficult to see, even with a microscope. Under optimal conditions it will go from egg to adult in 3 to 4 weeks. This is much quicker than Macrolophus, a similar mirid bug that takes 6 to 8 weeks to develop from egg to adult. Optimal development conditions are around 23ºC with some humidity.
When compared to predatory mites the development and population increase of predatory mirid bugs is relatively slow. This means that timing of introductions can be important to ensure that bugs are on the crop in sufficient numbers to control the pests as they occur. However the fact that Nesidiocoris tenuis will feed on the plant may result in plant damage if the population is high with no pests to eat. If the target pest is Tuta absoluta the preferred introduction strategy is to introduce low numbers early in the crop cycle. Where whitefly is the target pest later introductions may be better.
When established on the crop Nesidiocoris makes a significant contribution to the control of other pests such as spider mite and leaf-miner, but is not recommended specifically for control of these pests. Spider mite in particular is a poor quality diet and results in slow growth and low fecundity. It is important to note that Nesidiocoris tenuis and other generalist predators may have prey preferences and ignore one potential pest in favour of another that they prefer. Control of these less favoured dietary items will always be unpredictable.
When and where should you use it?
Nesiline t was developed originally the for control of whitefly on tomatoes but in more recent years it has been targeted more at the South American Tomato Moth Leafminer (Tuta absoluta). It is recommended for use on tomatoes and aubergines only. All tomato varieties can suffer damage from Nesidiocoris tenuis if high populations build up. As pest populations decline, the Nesidiocoris become more phytophagous and this feeding can result in necrotic rings on stems, leaves and flower trusses, causing fruit drop and a potential loss in yield.
On tomatoes and aubergines, early release gives the best result. Release rates of 0.25-2/m² are recommended, depending on previous season experience of pest problems. Initial releases can be accompanied by use of sterilised eggs of the stored product moth Ephestia, which may help initial establishment of Nesidiocoris in the absence of prey.
How should you use it?
Release Nesidiocoris as uniformly as possible throughout the crop, preferably in subdued light early or late in the day to avoid adults flying directly to the vents.
Open the pack where it is needed and walk along the plant rows, gently shaking the container to distribute the adults. Alternatively, pour small amounts of products onto leaves or into a release box (URB). Leave the packaging at the base of a plant to allow any remaining adults to leave.
When should you not use it?
Nesiline t has been reported to cause leaf damage and fruit loss in some tomato crops Cherry and vine ripened tomatoes are most at risk, and Nesidiocoris should only be used on these crops when there is a serious risk of damage from Tuta absoluta, other methods of control are not available, for example on organic crops. In conventional crops use of recently introduced chemical controls would be a preferred approach.
It should not be used on ornamental crops without a trial treatment of a small number of isolated plants.
What will it do?
Nesiline t will help prevent the build-up of high populations of Tuta absoluta and whitefly in round tomato and aubergine crops when used as recommended. It will also contribute to control of other pests once it has established.
What will it not do, and what are the control options?
Nesiline t will not quickly reduce high existing whitefly or Tuta absoluta populations unless used at very high rates.
It is not recommended for use to control other pests such as spider mite, although once established in the crop it will contribute to their control.
It is not recommended for control of whitefly on cucumber or pepper crops.
Chemical compatibility
A number of chemical insecticides can be integrated with the use of
Nesidiocoris tenuis. Some will result in a reduction of the population as a result of direct toxicity to certain stages, or as an indirect result of prey removal.