Recent hot weather has seen a dramatic rise in pest populations especially on glasshouse crops such as tomatoes, peppers, cucumbers and aubergines. As well as damage caused from feeding, such high pest poulations can also increase incidence of potentially devastating viruses such as tobacco mosaic virus. Western flower thrip, whitefly, greenfly, red spider mite and caterpillars are causing widespread damage and action may be required to protect your crops.

Western Flower Thrip. Quite difficult to identify, this tiny pest can cause severe damage and is difficult to control. In severe infestations leaves can appear speckled with white russeting, leaves can turn yellow and shoots and fruits can be severely distorted. A magnifying glass may be needed to spot the tiny yellowish sickle shaped creature, often found in flowers (try tapping the flowers onto a piece of paper) and also on both sides of leaves .Cucumbers and Aubergines are particularly susceptible. Most pesticides are ineffective against W.F.Thrips , however Provado Ultimate Bug Killer should offer some degree of control. Biological control is possible with Amblyseius (available mail order from specialist suppliers)  but may struggle to combat very rapid build up in hot weather. Consider removing badly infected flowers and leaves, and in severe cases entire plants. Damping down foliage in hot weather can help reduce damage from the pest feeding on the plant and yellow sticky traps are useful to monitor pest levels.

Whitefly. Major pest of tomatoes and many ornamental plants, especially fuchsias. Adults are easily identified but look out for the scales on undersides of leaves which will hatch out into adults causing clouds of bugs! In severe outbreaks feeding causes leaves to become sticky and this sugary secretion can turn black as it is colonised by sooty moulds. Biological control is effective using a tiny parasitic wasp called Encarsia formosa which lays eggs in the whitefly scales turning them black and killing the whitefly pupae. (Available mail order from specialist suppliers) Unfortunately established pest populations are difficult to eradicate with Encarsia, introduction is required at regular intervals throughout the growing season for effective control. Again most pesticides are useless against Whitefly although Provado Ultimate Bug Killer should provide some control. Organic sprays based on soap and fatty acids may be useful but complete coverage of both sides of the foliage is required. Sticky yellow traps hanging in the crop may also help.

Red Spider Mite. A tiny pest which can cause a huge amount of damage especially on Cucumbers and a wide range of ornamental plants. A magnifying glass is helpful to spot the tiny pest which is often found on the underside of leaves. In severe cases foliage becomes blotchy, chlorotic and straw like and may eventually become covered in cob webbing. Biological control is effective using Phytoseilius persimilis, available mail order from specialist suppliers and can be used to eradicate established populations. Most pesticides are ineffective. Damping down of foliage may help reduce feeding damage. Space plants out so that leaves are not touching to prevent spread from plant to plant. Destroy badly infected leaves and plants.

Caterpillars. The young stage of many butterflies and moths cause severe damage to crops at this time of year, especially members of the Cruciferae (cabbage) family. Quite easily controlled with Scotts Bug Clear Gun (Make sure its the one with bifenthrin as the active ingredient). Organic gardeners can try soap based products and pick off caterpillars by hand. Birds can be very helpful too so look after them!

well not oil, but something almost as valuable…water! With an annual water bill in excess of £20,ooo ways of reducing water consumption and water costs are being actively investigated at Snowdonia Nurseries, Glan Conwy. Drilling began at the end of June to search for a supply of water from below ground to supplement the mains supply and reduce costs. As of today (6th July) water has been found at a depth of approx. 75m but further work is needed to ensure that the quality is pure enough for irrigation purposes, and that the supply is sufficient to feed our very thirsty overnight irrigation system. If successful the cost of drilling should pay for itself within 2 years and help reduce overheads in years to come. The possibility of harvesting rain water runoff from the glasshouse roofs is also being investigated for watering the glasshouse crops. Read the rest of this entry »