Which Pests like Eating Potatoes?

Posted on: May 14th, 2011 by Annette Welsford 3 Comments

Growing your own potatoes can be a lot of fun, and if you get it right, rewarding too. But we aren’t the only creatures that like potatoes, and you need to take steps to ensure that pests don’t eat your potato crop before you get a chance to harvest it.

Whilst you can’t see the potato tubers growing underground, you can get see from the leaves above the ground whether the plant is healthy or not. If it doesn’t look anything but perfect, take immediate action.

Of course it may not be that pests are actually eating your potatoes. Insects also transmit viral diseases, so it’s just as well to check for disease as well as infestation of typical potato pests.

Some pests occur below the ground, while others, which are usually quicker and easier to spot, are found above the ground.

Common potato pests (in alphabetical order) include:

  • aphids

  • Colorado potato beetle

  • cutworm

  • flea beetles

  • nematodes

  • potato leafhopper

  • potato psyllids

  • silver whiteflies

  • snails and slugs

  • tuber moths

  • wireworms

Both green peach and potato aphids love potato plants. Sometimes referred to as “plant lice”, because of their minute size, they suck the juice out of the plant. Apart from the damage they cause, they also transmit viral diseases.

The Colorado potato beetle, as its name suggests, is native to Colorado in North America. It is now found through North America and has also spread to Europe and other parts of the northern hemisphere. Attacking the underside of leaves, both the adult beetle and it’s even more damaging larvae, can chomp all the leaves on a potato plant within days.

Cutworms can cause considerable damage to the young shoots of potato plants. If you don’t spot them and take action early on, the plant is likely to suddenly wilt and die. Tubers may also be damaged by the larvae of cutworm. The problem is that they tend to burrow under the surface of the soil during the day, so it’s a good idea to take precautionary steps to stop them before they start.

Flea beetles are tiny little creatures no more than 2 mm or 1/16th of an inch long that attack potato leaves from the underside. You know that they are at work if you see lots of little holes in the leaves of your potato plants. Not only can this damage lead to early blight, but where there are beetles, you can be sure that there are flea beetle larvae chomping away on your below-ground tubers.

Potato Leafhoppers

Relatives of both the leafhoppers
and aphids, potato psyllids are
also suckers.

If you spot little brown, triangular shaped holes that look as if they have been caused by drought, chances are potato leafhoppers have found your potatoes. Even though they can fly relatively long distances, they are reasonably easy to control.

Relatives of both the leafhoppers and aphids, potato psyllids are also suckers. Although they only feed on leaves, the damage they do can kill potato plants. At best, tubers will be stunted and will develop odd shapes. If attacked by psyllids, the tubers cannot be used for seed.

Nematodes are microscopic worms that damage and stunt many types of vegetables. The most serious nematode potato pests are potato cyst nematodes and root-knot nematodes (also called eelworm). You could say they are the scourge of potato plants since the damage they do can be devastating, and they are generally difficult to control.

Potato tuber moths are nocturnal insects that lay their eggs on the underside of potato leaves and any part of the tuber that might be exposed. It isn’t the moth itself that does the damage, it’s the larvae that emerge from the eggs that attack both foliage and the tubers. Starting out at about 2 mm in length, the caterpillars grow to about 18 mm, sometimes even longer. They tunnel through the foliage and tubers, rendering them inedible and unusable for seed. You can spot an infested tuber relatively easily because this potato-eating pest leaves behind a mealy debris or frass in its tunnels and at the tunnel entrance.

Silver whiteflies are the most common type of whitefly that infests potato plants. They are tiny (even smaller than flea beetles) and usually found on the underside of leaves, causing the same sort of damage as tiny aphids do. Happily, there are insects that don’t like potatoes but do like silver whiteflies, including some wasp species.

Both slugs and snails can be troublesome, particularly when the weather is wet. But at least you can see them and bait them.

Like the potato tuber moth larvae, it is the larvae of the click beetle – called wireworms – that does the damage. Unlike the potato tuber moth larvae though, they don’t tunnel right through the tuber. Damage is usually in the form of 10 mm-long holes that they make in the tubers.

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  • Gail Davis

    We have grown potatoes for years and all the pests mentioned above have been taken care of. However, this year, the plants are healthy and for a couple of weeks we have been getting perfect potatoes. This week we have found that something is eating them underground. There are not traces of moles or anything else but when we dig them several are split, with what appears to be gnawing marks. Any ideas? We live in South Carolina.

    Thanks!
    Gail

  • Cecilia

    Our potato plants died back way too soon this year and it is not caused by the weather. When we came to harvest them, not only did we get very few but about 50 % had holes in them, some completely drilled through. When digging we found this 5-10 cm insect in the ground that we suspect, it’s beige and has mandibles, claws and a stinger, it looks like a combination between a grasshopper and grub (frankly, it looked like nothing we’ve ever seen before). What is it and more importantly, what can we do about it (pesticides not allowed).

    thanks for any suggestion

    Cecilia

  • opinionated

    I just pulled in this years firs potato crop (and my first successful planting) and nearly 1/3 of the potatoes looked half eaten. What kind of underground pest am I likely to be dealing with here, and how can I stop them? I am in Georgia, zone 7/8. Thanks for your help