Tomato Bugs and Pests

Much as we love tomatoes, so too do a number of bugs and other pests. For this reason it is essential to keep an eye out for those that are most common and to take corrective action as soon as you spot them.

Tomatoes are also susceptible to a number of quite common diseases, so you need to differentiate between the effects of these, and the damage that is likely to be caused by pests (including bugs).

Common Bugs

Universally, the most common pests and bugs that are likely to attack your tomatoes are:

• cutworms,
• caterpillars,
• white flies,
• mites,
• nematodes.

Cutworm

Cutworms, which are a type of caterpillar larvae, feed at night, and it is not uncommon to suddenly find that seedlings look as if they have been sliced off at the top. They seem to be particularly troublesome when tomatoes have been planted out in heavily-manured ground. Ironically, the adult moth – which flies at night – feeds on the nectar of tomato flowers, but does no damage at all.

The caterpillars of both the American bollworm and tomato looper can cause an enormous amount of damage. The moth lays its eggs on the leaves of the tomato plant and when the larvae hatch, they move quickly to the fruit, tunnelling through the young tomatoes as they feed.

Whitefly is one of the most serious pests tomato growers have to contend with, particularly when tomatoes are grown in a greenhouse. These little pests gather together on the underside of leaves, secreting a sweet sticky substance that promotes “sooty mould”. The flies grow to about 1 mm in length and can sometimes be seen flying around tomato plants. When they feed on upper leaf surfaces, they cause the leaves to look pale and spotty.

Various types of mites enjoy eating tomatoes! White-yellow speckles on leaves together with a decrease in plant growth, indicates the presence of spider mites. Tomato russet mites cause leaves to turn a bronze colour. They also affect plant growth and can cause fruit to become disfigured. Another type of microscopic mite causes a condition known as erinose, which irritates the stem and leaf tissue and results in a white furry look similar to mildew. Affected leaves usually dry up and fall off.

Bollworm

Parasitic nematodes or “eelworms” are microscopic roundworms. Because they are so tiny, and because they feed underground, we don’t see them and often are not aware of the tremendous damage they cause. Tomatoes are very susceptible to nematodes, so at least you are forewarned. You can usually identify nematode damage by swellings on the roots. If the tomato plants appear to be dying for no particular reason, pull them out and examine the roots.

Other bugs to look out for include fruit fly, stink bugs, thrips and aphids.

If you are on the look out for a detailed, easy-to-understand guide on bugs and pests that affect tomatoes, pick up our book, How To Grow Juicy Tasty Tomatoes.