Vegetable Garden Pests - Identification & Prevention
Seeing your vegetable crops decimated by garden pests can be a very disheartening sight and it can happen seemingly overnight if proper preventative methods aren't applied. Once the garden pest or pests have been identified you can go about controlling them. Most insects and wildlife found in the vegetable garden are not pests, around 95% are beneficial or harmless. The best gardens are teeming with life, and maintaining the right balance of beneficial pests and wildlife while reducing or eliminating the populations of damage causing insects and pests is what pest control is all about. The easiest and most cost effective method of controlling pests is to use natural and preventative means and there are a few that work for every pest. Here is a run down of the most common and devastating veg garden pests.
Allium Leaf Miner
Onions, garlic, shallots and leeks are susceptible to this species of fly. The adult fly and maggot cause damage to the foliage and bulb, leaving it prone to rot and fungal infection. If an outbreak is suspected the young plants should be protected with fine mesh netting in spring and autumn.
Animals & Pets
Deer, rabbits, cats, dogs etc. Cats and dogs generally don't eat plants but they can ruin them by fouling, there are an abundance of electronic devices for deterring them as well as sprays and pellets. Rabbits and deer will happily eat through your vegetable crops and can be very difficult to catch or get rid of, making crops inaccessible to them is the best defence. There are plenty of safe products that emit a smell to deter grazing wildlife. Once an animal gets a good feed in your garden they will keep coming back and probably bring others with them. The use of poison can have a detrimental effect on other wildlife so organic methods are strongly encouraged.
Aphids, also called plant lice, greenfly, whitefly, and blackfly among other names, are among the most destructive insect pests to garden plants in our region of the world, they are tiny insects that form huge colonies and cause havoc in the vegetable garden. They are sap eating insects that will feed on just about any plant in the garden, and as a bonus their saliva is toxic to plants and the often transmit diseases too. Plants affected by aphids will display a lack of vigour, yellowing foliage, leaf curl, stunted growth, and very low yields. Ladybirds and wasps are natural predators and feed on many different species of insect pest, including aphids but leave plants alone. More effective results can be achieved by spraying with a good organic insecticide.
Birds & Butterflies
Shortly after sowing seeds, birds and butterflies can become a problem. Making it difficult for birds to access your vegetable garden will stop them from destroying it, some mesh netting placed across freshly planted seeds or seedlings will keep them away and give your garden a chance. Bird netting will also prevent butterflies from laying their eggs on your crops, these eggs turn into caterpillars which will decimate cabbage plants etc. The netting can be laid directly on the area that has been planted but it should be placed on supports to raise it off the plants once they start growing.
There are many bird scare methods including the trusty scarecrow that each have varying levels of effectiveness. Bird scare line can be strung around crops, the line hums slightly with the wind and emits a slight vibration that deters birds, video and audio tape can be used for this also. Hanging various small reflective items like old cds or bits of foil on a line also works but the birds can become used to them if their positioning is not changed periodically. We recommend using the birds away kit as it's a bit more sightly than hanging cds around the vegetable garden.
Cabbage Root Fly
Cabbage root fly is a small grey fly a bit like a small house fly. It lays it’s eggs at the base of brassica seedlings, the eggs hatch into maggots and then burrow down to feast on the new roots of your plants. Plants will become discoloured and will start to wilt due to the damaged roots. Identifying the cabbage root fly can be done by digging up the plant and visually inspecting the roots. These are one of the easier garden pests to control, a cabbage collar or similar piece of material placed around the base of a plant will prevent the fly's maggots reaching it's roots.
Cabbage White Butterfly
The caterpillar of the cabbage white butterfly can cause extensive damage to all brassicas, stripping leaves and tunneling into roots. The butterfly lays her eggs on the underside of brassica leaves and once hatched the caterpillar starts eating right away. Vigilantly remove caterpillars and eggs and protect plants with netting or mini polytunnels. The eggs are yellow and will be under the leaves out of sight. Encourage predatory birds by hanging feeders nearby.
The Cabbage whitefly is an aphid (Like a greenfly, except white), it is less troublesome than other cabbage pests but worth keeping an eye on. The adults are tiny white insects which you’ll find on the underside of the leaves. They produce a sticky substance called ‘honeydew’ which will probably cause a grey mould later. Remove any yellowing leaves at the base of the plant as they may be harbouring aphid eggs. You can wash off whitefly, honeydew and grey mould with a strong jet of water.
The fly larvae tunnel into the roots of carrots, parsnips and celery rendering them inedible and prone to rot. The low flying insect can be deterred by using 2ft/60cm mesh or polythene screens. Planting onions or other strong smelling plants nearby will mask the carrot smell which attracts the fly.
Cutworms are fond of cabbage and other brassicas, peppers, and tomatoes. They get their names because the hungry moth larva feed on the roots and stems of vegetable plants in mid to late summer and the entire plant will wilt or get cut off at the base. Cultivate the soil throughout the season by hoeing and weeding to prevent further pupation and expose the larvae.
Rodents like mice, squirrels, voles, moles, and rats can be a nuisance in the vegetable plot but can be easily prevented. Mice and voles are active all year round and will feed on germinating seeds, plant stems, tree bark and stored produce. Rats will eat almost anything and can find a nice steaming compost heap particularly attractive. Trapping or the introduction of a cat will discourage rodents. Barriers work well most of the time especially electronic barriers that emit multi-frequency noise that deters them. Prevention techniques such as clearing or blocking any areas that rodents could nest like in long grass or beneath a porch work well.
Slugs & Snails
Slugs and snails are a pest that have a presence in every garden and cause more damage to vegetable crops than most other pests. Controlling this menace is an on-going battle for all gardeners, and it seems that it is impossible to be free of them. At night time they feed on most crops; damaging foliage, roots, stems and bulbs before retreating out of sight in daylight. What makes them so formidable is that they are hermaphroditic and lay their eggs only a few days after reproduction. They lay an average of about thirty eggs and these can lay dormant in the soil for years.
Slugs and snails can destroy foliage faster than the plants can grow. It can be quite a messy business getting rid of them but there are many effective methods and products to consider. Beer traps, copper barriers and organic ferrous phosphate based pellets will have some impact while encouraging birds and frogs to the garden, their natural predators, will help to keep the population at bay. It is possible to hunt for them with a torch at night while they are active and physically remove them.
Spider mites are sap-sucking insects that cause damage to foliage in greenhouse plants like tomatoes and cucumbers. Spotting an infestation of these pests is easy enough, leaves will start to yellow and you will see very fine spider webs under the leaves and on the stem. Frequent applications of soapy fatty acid solutions will help control the spread of the mite.
The larvae of click beetles are laid into the soil in late spring and when grown cause damage to roots and tubers, particularly potatoes. Plants will become yellowed and wilted and may cease to grow altogether. There is no treatment for this pest outside of insecticides and preventative action is achieved by physically inspecting and removing them. Turning the soil to expose the wireworm to other predatory wildlife is recommended.
Whitefly are a number of species of tiny white insects that feed on plant foliage and the larvae leave a sticky deposit behind which can cause mould. They fly from plant to plant and can ravage an entire greenhouse or polytunnel. Regular spraying with a soapy solution and encouraging the presence of spiders will help to curtail them.
Many pests will remain in the garden causing minimal damage to crops, gardeners often accept this and even refer to it as "nature's tax". It is up to the gardener to determine how much damage they can tolerate. By understanding the pests in the garden the vegetable grower can identify potential problems and intervene early enough to prevent further damage. Regular inspections will help eradicate the unwanted pests on most plants and establish a healthy growing environment.