Beat the spring pests
Taking action now will save you from a summer of battling beasts
Spring has finally sprung the garden into life but it also means many pests are growing rapidly alongside your plants – and managing them now will stop them from causing havoc.
To begin, think twice before picking up the chemicals, because some simple tricks can stop pests ruining plants without the need to resort to the spray gun.
A healthy, strong-growing plant is also more likely to be able to shrug off a pest attack than a weak, struggling one, so start by making sure to water, feed and repot plants when necessary. It’s your first line of defence against a pest attack.
Here are the 15 pests most likely to start feeding on your precious plants now.
1 Carrot fly
If you’ve harvested carrots that have been tunnelled into, it’s most likely the work of the carrot fly. You can build a mesh barrier 60cm (24in) tall with a roof to place over your crop if you sow carrots now, but there are other easy steps to lessen the risk. Grow resistant varieties of carrot such as ‘Resistafly’ and ‘Flyaway’ (both from Thompson & Morgan).
Carrot flies are attracted by the scent of the foliage, which will be stronger if you have to thin out carrot seedlings. Sow them thinly now so that you don’t need to thin them out or allow an entry point for the flies to lay their eggs. Carrot flies emerge and lay eggs in May, so delay sowing until early June (sow quickmaturing varieties such as ‘Early Nantes 2’). A second generation of carrot fly will lay eggs in September but you can avoid this by harvesting at the end of August.
2 Slugs and snails
There are lots of ways to deter these pests before resorting to pellets.
Encourage slug eaters Frogs, toads and ground beetles will all eat slugs, so if they call your garden home they can reduce the slug population. A pond will encourage frogs and toads and a woodpile or compost heap will attract ground beetles to the garden.
Use nematodes These natural predators can be effective at getting rid of slugs below ground, which can decimate potato crops. Nematodes work best when watered into damp soil when soil temperature is at least 5C (41F) and no more than 20C (68F).
Grow above ground Grow slug-prone crops such as strawberries, courgettes and tomatoes in pots. Spray the outside of them with WD40 to make it harder for slugs or snails to climb up.
3 Vine weevil
Adult weevils will start to leave tell-tale signs of their presence in spring: neat notches eaten from the edges of leaves. They’re most active at night, so inspect vulnerable plants, such as heucheras, rhododendrons, euonymus and hydrangeas, and collect the grubs into a bucket and dispose of them. The larvae eat plant roots in autumn and few plants will recover from an attack. Always check for the cream coloured larvae in the compost when repotting a plant.
4 Rabbits
Possibly inspired by the Peter Rabbit movie, rabbits will be eyeing up young veg plants right now! Larger plants aren’t as desirable to them so grow young plants on in pots in cold frames or a greenhouse for as long as possible so you can plant out sizeable specimens. Cover young plants that are in )the ground with fleece.
5 Lily beetle
These blood-red beetles can be easily controlled if you inspect lilies regularly as soon as the shoots start to grow. The beetles are easy to find and picking them off by hand now will prevent them from munching through the leaves and turning them to ribbons.
6 Greenfly
These tiny pests are very good at camouflage and if you look closely at young, soft shoots of any plant now, you may find them grouping together. As well as sucking sap from the shoots and weakening them, some aphids can also transfer viruses. The easiest way to remove aphids is to blast them off with a jet of water from a hose, or wipe the shoots with a damp cloth to remove them.
7 Box tree caterpillar
This was named the number one garden pest of 2017 by the RHS. This caterpillar can eat all the leaves from a box plant, leaving a fine webbing over the plants. The plants can be sprayed but bear in mind if you have a box hedge it will be hard to have every leaf covered. Inspect the plants for the caterpillars and pick them off by hand. Nematodes may help control them, too. The one to use is Nemasys Fruit and Vegetable Control, despite the confusing name!
8 Viburnum beetle
Larvae of this pest can strip a viburnum of leaves. The only effective method of control is to spray. Try regular applications of the organic pesticide Bug Clear Gun for Fruit or Defenders Bug Killer for two to three weeks. But never spray when the plant is in flower.
9 Scale insects
These bugs suck the sap from plants and leave a sticky substance on the underside of leaves, which turns to black fungus. They breed all year round on indoor plants. Check the underside of leaves on indoor plants for signs of young scale insects and use a damp cloth to wipe them off the leaves.
10 Cabbage root fly
Don’t forget to place circular collars around the bottom of brassicas to stop these flies laying eggs. Make the collars out of roofing felt, fabric weed suppressor or thick cardboard.
11 Woolly aphid
These aphids leave a white, fluffy substance on stems, often on apple trees, and they start feeding now. Inspect the branches of apple trees and scrub them with a stiff brush if you find the aphids.
12 Fuchsia gall mite
This microscopic pest has been active in the UK for around 10 years. It sucks sap from the shoots of fuchsias and its first generation emerges in spring. There’s no chemical that will effectively control this pest but snipping off affected shoots down to unaffected growth will remove a lot of the mites and limit the damage. Bin or burn the affected plant material.
13 Pigeons
One of the most frustrating pests, pecking at many vegetable and salad crops to leave nothing but a thin stalk where a lush, leafy plant once lived. Bird scarers are a must, as is finely meshed netting placed over vulnerable crops. Staple netting to a wooden frame and place it over raised beds or veg beds to keep them safe. Avoid putting out bird food that contains grains such as corn, wheat and barley because this will just attract more pigeons to your plot.
14 Pear blister mite
This pest causes bumpy pink and yellow blotches to appear on the leaves of pear trees, which become black later. If it has affected just a few leaves, remove them now and it will help to stop it spreading further, although the damage is only cosmetic!
15 Glasshouse mealybug
These bugs stunt the growth of greenhouse plants. They lay eggs on dead leaves and old bits of stem, so tidy up and bin or burn old plant material where they might be hiding. They’re fairly tolerant of sprays but you can buy ladybirds that eat them from www.defenders.co.uk.