Organic Controls for Garden Pests
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Thrips are tiny, tiny insects that feed by burrowing into plant tissue or developing leaves and buds. In the open garden they tend to cause most damage from June to September, but in a glasshouse they can often start in April.

Thrips are only about about 1mm long, so difficult to spot. If you get close up to them and use a magnifying glass you can see that they are cigar-shaped, long and thin, in various colours of yellow, brown and green. The photo on the right shows a young wingless thrip ("nymph") on the left and two adults on the right.

The larvae live on the plant, but when they pupate the pupa often drops to the soil. The pupae may hide on the soil compost for several days or several months before the adults emerge, so remember that soil can be a source of infection.

Click here for Thrips Control

Thrips are commonly known as Thunder Flies. There are different thrips found on different plants - rose thrips and gladioli thrips have been with us for a long time, but the major threat to commercial crops at the moment is the more recent "Western Flower Thrips"(Frankliniella occidentalis). The adults lay their eggs in a pocket in the leaf, and the larvae emerge to feed on the plant - growing buds and flower buds are particular targets.

Identifying Thrips

Thrips suck juices out of leaves and emerging flowers, leaving them with a 'rasped' look. They do not generally kill plants, but make them look tired and unsightly. If they attack young emerging shoots then leaves may be crooked and misshapen. The trio of phots below shows a) distorted mishapen pepper leaves which is a sign of shoot damage and b) distorted fruit which is a sign of flower bud damage and c) leaves attacked by adult thrips

Controlling Thrips

There are three main biological controls for thrips..
Mites which crawl around the plant feeding on thrips larvae (Amblyseius cucumeris) more about plant based mites...
soil-based mites that eat the thrips pupae (Hypoaspis miles) more about soil based mites...
nematodes that live in the soil and eat the thrips pupae (Steinernema feltiae). These are the same nematodes used to treat leatherjackets more about nematodes...

Plant Based Mites Amblyseius cucumeris

Amblyseius cucumeris is a tiny, pale coloured beneficial mite. It is used by professional glasshouse growers to control thrips, and also tarsonemid mites, and can be used in gardens outside in the summer months in sheltered areas. These mites crawl around on the leaves and within the flower buds looking for their favourite prey which are thrips larvae. They usually target the smaller, newly hatched young, but they have been known to tackle larvae bigger than themselves. More information...

Giant Shaker Tub 50,000 mites
27.95 inc P&P

10 sachets - 10,000 mites

50 sachets - 50,000 mites

200 sachets - 200,000 mites

Soil-Based Mites Hypoaspis miles

These are tiny brownish crawling beneficial mites which eat lot of different microscopic creatures in the soil including. thrips larvae and sciarid fly larvae. The soil temperature needs to be above 12C, and they will be even more effective if the soil is warmer than that. Use as soon as possible after receipt, and within 48 hours. Store at 15-20 C until use. Keep out of direct sunlight. For more information about hypoaspis mites click here

Small tub 10,000 mites
23.95 inc P&P

Large tub 25,000 mites sufficient for 125 sq metres
42.95 inc P&P

Nematodes Steinernema feltiae

These are tiny transparent worms (eelworms) which live in the soil. These nematodes are active at temperatures as low as 8C, but the bacteria that they use to kill their hosts are not, minimum soil temperatures need to be 14C for the nematodes to work effectively.
The nematodes which are bred to kill leatherjacket larvae Steinernema feltiae are also effective in controlling thrips larvae. For more information about nematodes click here

Standard Pack - 100sqm
24.95 inc P&P