Neoseiulus cucumeris, which is the best format to use for your ornamental and vegetables greenhouse crops?

Neoseiulus cucumeris is a predatory mite that has been used for over 35 years to control thrips around the world. Mainly introduced in horticultural and market garden greenhouses, this generalist predator can control the two main species of pest thrips found in greenhouses: western flower thrips (Frankliniella ocidentalis) and onion thrips (Thrips tabaci).

IIt can also be used to control greenhouse broad mites (Polyphagotarsonemus latus), a tiny predatory mite that is a growing problem for ornamental plant growers and importers.

In the last several years, this product has been available in several formats, including slow-release packets, in bulk on bran and in bulk on vermiculite. Each format has its advantages and limitations. How to know which to use to maximize pest control?

Slow-release cucumeris packet

The slow-release cucumeris packet consists of a water-resistant paper packet containing a mix of predatory mites, flour mites (prey) and a substrate (bran).

The packet becomes a sort of mini nursery that gradually produces predatory mites for 4 to 6 weeks. There is a tiny hole on the front and the back of the packet, from which the predatory mites exit to colonize the surrounding plants.

Two formats are available: small packet (250/1,000 mites) and large packet (1,000/5,000 mites). See explanation below.

Table 1. Comparison of the cucumeris packets

Cucumeris slow-release packet: on a hook or stick?

Most slow-release packets on the market are installed with a hook, although packets on sticks have been gaining in popularity over the last few years. Sticks let you position the product directly in the midst of the plant’s foliage, thus greatly reducing the negative effects of direct light and dryness.

Be sure to properly position the packets!

Slow-release packets are very sensitive to direct light. It is therefore important to position them within the plant’s foliage. Improper positioning will reduce the longevity of the packets and could even kill the predatory mites early on in the treatment.

Be careful not to widen the hole!

The small hole on the front and the back of the packet must not be widened. It is the ideal size to let the predatory mites emerge, while keeping the packet humid enough to favour the development of the juveniles and eggs. If the hole is widened, the packet risks not producing as many predatory mites.

Applying cucumeris in bulk

Applying cucumeris in bulk involves sprinkling the mites directly on the plants, either by hand or mechanically. Depending on the type of production, introductions can be every week, every two weeks or every three weeks. This application method introduces a large quantity of predators and is ideal for moderate to severe infestations. Two substrates are available: bran and vermiculite.

Cucumeris in bulk on bran

Cucumeris in bulk on bran involves bottling the substrate used to produce Neoseiulus cucumeris in the laboratory. This technique has the advantage of containing all stages of development (eggs, juveniles and adults) as well as prey for food. It is more effective for moderate to severe infestations.

The main disadvantage is that when it gets wet, bran tends to stick to the leaves of the plants and cause mold spots. It is therefore not recommended for ornamental plants.

Cucumeris in bulk on bran

Cucumeris in bulk on bran involves bottling the substrate used to produce Neoseiulus cucumeris in the laboratory. This technique has the advantage of containing all stages of development (eggs, juveniles and adults) as well as prey for food. It is more effective for moderate to severe infestations.

The main disadvantage is that when it gets wet, bran tends to stick to the leaves of the plants and cause mold spots. It is therefore not recommended for ornamental plants.

Table 2. Comparison of cucumeris in bulk on bran and on vermiculite

* Depending on the infestation level, the type of plant and its growth stage.