Pest control within the growroom is of paramount importance. Having grown your plants and nurtured them, to see your labours destroyed, in a relatively short space of time, by some kind of mobile, insect, macerator can be very disheartening. All is not lost however, because there is an army out there waiting to come to your rescue. The most common types of damaging insects are now able to be controlled by natural means.

How does it work you ask?

Each damaging insect has a natural predator. These beneficial insects can be introduced to the infested growroom and will immediately start to destroy the damaging insects. Each species of predator is specific to one, or sometimes two, species of insect. What this means is that it will only attack and destroy the insects that you wish it to destroy.

The three main insects that affect the growroom are Whitefly, Red Spider Mite and Thrips. For each of these threats there are voracious predators waiting for the opportunity to attack and destroy them.


A major devourer of vegetable and ornamental crops, this sap feeding insect, will leave plants sticky and messy, and can spread plant viruses. The adults and nymphs both feed on the plant. The whitefly adults are present on the underside of leaves and on larger plants like Tomatoes, nearer the top of the plant. They deposit their eggs on the underside of leaves, where the larvae develop. Plant growth is stunted and fruit can be soiled with heavy infestations.

Small Wasps That Attack Whitefly Larvae.

The most serious threat species of whitefly are the glasshouse whitefly (Trialeurodes vaporarium) and the tobacco whitefly (Bemisia tabaci). The glasshouse whitefly is more common to the UK. but tobacco whitefly is now starting to occur.

One safe and effective way to control whitefly is by using its natural enemy, the parasitic wasp Encarsia formosa. Whitefly killer is supplied as Encarsia formosa pupae on cards. The cards are hung on the infested plants. Tiny parasitic wasps hatch from these cards and fly off to parasitise whitefly pupae. The whitefly pupae turn black after 10 – 14 days depending on the temperature. These will in turn produce more encarsia formosa which will control further the whitefly population. These tiny insects only attack whitefly and are harmless to all other creatures.

Red Spider Mite.

There are two types of common red spider mite; glasshouse red spider mite Tetranychus urticae and Fruit tree red spider mite Panonychus ulmi. Damage caused by these mites can be significant when they occur in high numbers. As plant sap feeders, the first sign of damage is a speckling on leaves eventually turning them yellow. Young plants growth is distorted and older plants loose their leaves. Fine webbing is formed, which is then used to transport very high numbers of red spider mites about.

The Predatory Mite Phytoseiulus Persimilis

These predatory mites are shaken over the infected leaves or poured into a distribution box and hung on high or taller plants. The predatory mite reproduces at twice the rate of red spider mite at 18 degrees Celsius and eats the eggs, young and adults of the spider mite. Spider Mite control should only be applied after red spider mite have been observed and works better with higher humidity. Phytoseiulus persimilis are also more effective in greenhouses or conservatories. In optimum conditions it will consume more red spider mites than Amblyseius californicus.

Spider Mite Killer Important facts:

Supplied as young and adult predators in shaker bottles of 500 or 2000 insects contained in a vermiculite carrier material, which should be shaken or poured onto the infected areas of red spider mite damage. For narrow leaves or tall plants hang the D-Boxes enclosed with your predators. Phytoseiulus require temperatures between 16 & 20C (61 & 68F) to be active and reproducing.

Always release your predators as soon after receipt as possible, this is a live product and unnecessary storage once received will result in the death of the predator.

Thrips.Adult thrips are tiny narrow bodied insects that vary in colour from yellow-brown-black. They feed by sucking plant sap. Thrips damage plants leaves, flowers and fruit by piercing and sucking out sap. After feeding, the surface of the plant has silvery-white mottled look on the leaves. They will also feed on the upper surface of the plant unlike most other plant sap pests. The young thrips or nymphs are wingless and creamy-yellow in appearance.

Just Orius.

Just Orius is a new product containing the predator; Orius laevigatus. This insect will feed on the larvae and adult of thrips. It will also feed on aphids. It is only suitable for use in greenhouses or conservatories. It is supplied in a shaker bottle, apply the predator throughout the plant.

Thrip Killer

Thrip Killer contains the predatory mite; Amblyseius Cucumeris. This tiny mite feeds on the Thrip larvae or young. It is supplied in a slow release bag or shaker bottle. The slow release bags produce a high number of mites over 6-8 weeks and can be hung on plants. This is recommended for preventative or low infestation treatments. The shaker bottle is for spot treatments of thrips and can be shaken over infected leaves where Thrip larvae are present. It requires a minimum temperature of 15C. Copyright Notice. Just Green is the leading supplier of biological control and other natural pest control products for gardeners. Comprehensive information and knowledge on biological control is available on Pests are controlled with nematodes and other natural enemies of pest nsects. Pests controlled include; Slugs, Vine Weevil, Red Spider mite, Whitefly, Aphid, Mealybug, Fungus fly, Thrip, Leatherjacket, Chafer grub and many more. Natural habitats are also produced by Just Green for beneficial insects and animals including Ladybirds, Bumble Bees, Mason Bees, Bats, Hedgehogs and Frogs. Children can learn about nature with Just Green Ladybird and Butterfly

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