Common pests in the garden
Aphids including blackfly, greenfly and whitefly
These are sap feeding insects, which infest shoot tips, flower buds and the underside of younger leaves. Feeding causes distortion to the plants and sometimes the affected area can wither and die. These insects also carry viruses through their biting mouthparts. Viruses can weaken the plant and cause stunted growth, leaf fall or other abnormalities to the flowers and leaves. For these two reasons it is best to remove aphids from your plants when they first appear. Aphids have many natural enemies in the garden, including ladybirds, lacewings and hoverfly larvae. Attracting a wide range of wildlife in your school garden will help with nature’s battle to keep numbers of the pests down to an acceptable level.
Methods of control include removing the pests and squashing them with fingers or spraying with a mild soap solution. Both of these should be carried out by an adult not the pupils. A biological control using parasitic wasps can be purchased. This is especially useful for controlling pests in glasshouses.
All children know that caterpillars turn into beautiful butterflies and moths, which we love to see in our gardens. When your entire cabbage crop has been decimated by caterpillars however it’s a different story! Caterpillars often feed on a specific crop - such as peas or cabbages.
Methods of control include inspecting plants regularly and picking off caterpillars where seen. Use a pathogenic nematode as a biological control. These nematodes enter the caterpillars' bodies and infect them with a bacterial disease.
Many larger birds can be a problem in the fruit and vegetable garden. They eat the emerging leaves and damage parts of many plants including brassicas and peas. Birds can also eat or damage ripening fruit such as apples, plums, cherries and currants.
Methods of control include using a scarecrow to keep the birds away (a great activity) or physically protecting the crop using fruit cages, netting or twigs.
Slugs & snails
Slugs and snails are so abundant in gardens that a certain amount of damage should be tolerated. You will want to protect your most vulnerable plants from damage or destruction. Both molluscs feed by rasping plant tissues with a toothed tongue. Slugs remain active throughout the year, whereas snails are dormant in autumn & winter.
Methods of control include covering young plants or seedlings with cloches or physical barriers, and encouraging more wildlife in the garden such as thrushes, toads and hedgehogs. Snails can be safely picked off and moved to an area outside the school garden. Use a biological control containing the nematode specific to slugs.
Vine weevil cause damage to plants in their larval and adult stages. The larvae feed on the roots of plants, especially those in pots or containers. The symptoms are similar to those of over or under watering plants as the roots are severed and unable to obtain water. The adult beetles feed only on foliage, causing notching on the edges of leaves. They are particularly fond of strawberries.
Control methods include picking off adults on warm evenings or trapping them with sticky traps. Encourage natural enemies (other wildlife) in your school garden such as birds, robins, frogs & toads. Use a biological control containing nematodes that specifically target vine weevil grubs.
Rabbits feed on a wide range of garden plants. New shoots and foliage can be grazed down to ground level, trees can be ring-barked and holes & scrapes dug in flower beds and lawns.
Methods of control include: fencing young trees and shrubs when first planted. The bottom 30cm should be buried below ground level to deter rabbits from burrowing underneath. Cover young vegetable plants with cloches.