Garden pests are perhaps the most notorious nemesis of the home gardener -- munching on foliage and flowers, sucking nutrients from the stem and leaves, and worse case scenario threatening fatal damage to garden plants. One of the best defenses against any type of pest is knowledge and prevention; keeping pests at bay is easier than trying to eradicate them after they’ve started causing problems.
Garden pests vary depending on the location/climate and the plants being grown. Some pests are not selective and will attack plants indiscriminately; other pests are species specific. Just as the pests vary, so do the treatments that should be implemented. Continuously scouting your plants for signs of an infestation is crucial; it is easier to treat when pests first appear, and when damage may still be minimal, than after it becomes a major problem.
Dark, damp spaces with ample green foliage or decomposing plant material are prime locations for garden slugs. As the canopy closes, shading the soil, it’s imperative to stay on the lookout for them. Slugs eat large holes in foliage, attacking most all garden vegetables and fruits. Young, tender, low-lying plants are at a higher risk for extensive damage, especially those with fruit close to the ground such as strawberries.
The most productive method of control is tediously hand picking slugs from the soil and plants about two hours after sunset. Diatomaceous earth or boric acid granules can be spread around the base of plants as a preventative to keep slugs from crossing the barrier. If the infestation is severe, trapping may be a more convenient solution; an easy trapping method is sinking shallow pans of stale beer into the ground – the yeast acts as an attractant, and the slugs fall into the liquid and drown.
With the potential to devastate complete brassica crops, reducing them to a skeleton of their former selves, the cabbage white is a force to reckon with. The large and small white butterflies lay their eggs on the undersides of brassica and caper crops; after a week or two the hatching larvae feed voraciously on the plants. Cabbage white can quickly wipe out entire plants if left unnoticed.
There is little in terms of chemical or biological treatments to handle an infestation; cabbage white butterflies have adapted to accumulate mustard oil in their bodies after feeding, making them inedible to most prey. The best way to avoid damage is to cover cabbage and other brassicas with butterfly netting to keep the adult butterflies from laying their eggs. Make sure the netting is secured tightly to the ground, avoiding any gaps where the insects can find a way in to the plants.
There’s much debate on whether or not ants are considered friend or foe of gardeners. Garden ants can help pollinate flowers as they travel looking for nectar, and they will feed on harmful caterpillars too. The tunnels they create within the soil help to aerate and improve drainage. A small infestation may not be problematic as garden ants do not feed on plants; the problems arise when a large infestation occurs close in proximity to the root system of plants because of the soil disruption they cause.
One of the most common, organic ways to get rid of ants is to make a borax and sugar mixture. Sprinkle the mix around the ant hills; the ants cannot tell the difference between the two products and will take both back to the colony. Borax is toxic to ants and should eradicate the colony within a few days.
With almost 3,000 species of butterflies in the United Kingdom it’s not a surprise to see caterpillars in the garden. While some like the cabbage white cause a huge amount of destruction, not every species has a negative impact on garden plants. Certain species of caterpillars will be attracted to specific plants; others are indifferent and feed on anything they can eat.
One of the best ways to combat caterpillars is to prevent butterflies from laying eggs on your plants. This can be done by covering plants with butterfly netting or physically removing eggs and/or caterpillars by hand. While tedious, this mechanical method may be one of the best ways to tackle an infestation. You can also plant strong smelling herbs such as lavender, sage, and peppermint to deter the pests, or allow your chickens or ducks to have free reign of the garden to pick them off as a snack. If none of these solutions are effective, neem oil can be applied to help control a caterpillar infestation.
Unlike other aphids that attack the leaves of plants, woolly aphids like the woody stems of apple, pear, prunus, pyracantha, and cotoneaster. The aphids feed on the plant sap, triggering knobby galls to form on the tree making them more susceptible to canker and other infections. Woolly aphids have a waxy white coating that gives them a “fluffy” appearance; infestations look like cotton wool and develop around cracks or wounds on trees.
When woolly aphids are first spotted, you can spray them with a jet of water to remove a large portion of the colony or scrub them off using soapy water and a brush. To prevent them purchase resistant apple varieties and encourage natural predators such as lacewings and ladybirds. Chemical pesticides containing pyrethrin or pyrethroids are effective, but care must be taken when trees are in bloom to avoid killing pollinating insects.
The vine weevil causes serious damage to ornamental plants and fruits throughout the UK -- especially those grown in containers (strawberries, cacti, succulents, cyclamen, begonia, and heurecha are especially at risk) -- making it one of the most destructive insect pests in the garden. Adult weevils eat plant leaves during the spring and summer; grubs cause the most damage by feeding on root systems during the autumn and winter months. Although unsightly, the damage caused by the adults doesn’t generally affect the growth of plants.
Adult weevils can be picked off plants by hands (best done after dark) or trapped with sticky barriers placed around the pots. Biological weevil killers are available that contain nematodes, and should be applied in August and September. Chemical control is achieved by drenching the compost around plants with dedicated weevil-killing insecticides, but cannot be used around edible plants.
Insects are not the only living creatures wreaking havoc on garden plants; birds are often a nuisance pest as well inflicting considerable damage on fruits and vegetables. On one hand they can be helpful by eating caterpillars, slugs and snails, but they also like to feast on the crops and seeds.
If birds are problematic, the best way to curb their damage is to protect your garden by covering plants with netting, or to set up scare tactics in an attempt to keep them away. Some great ways to scare birds away are to hang reflective tape or metal pie tins around the perimeter of the garden, set up a hawk or owl decoy, or employ the ever standard scarecrow.
Garden pests come in the form of insects and animals, and if left unchecked can cause an incredible amount of damage to plants. Trying to prevent pests from coming into the garden is the best strategy in many cases, but if they can’t be prevented the key to managing them is to catch infestations early and treat as soon as possible.