Rob Smith is dealing with troublesome caterpillars!
They love to nibble on fruit as well as leaves so keep a look out now
Touch wood, up to now I haven’t experienced that many pests on the allotment. That was until I saw a few holes in the leaves of my tunnel-grown tomatoes. They started off small and gradually got bigger over the next couple of days. These are typical signs of the tomato moth caterpillar. You’ll be forgiven for not knowing about them as they don’t seem to have been a problem until the last few years. The dull moth (unlike its brash American cousin) lays eggs on the underside of the tomato leaf and these eggs then hatch into tiny caterpillars that are difficult to spot.
The first signs of any problem will be small holes in the leaves, almost looking like the damage that flea beetle can do to brassicas – a series of small holes that are quite tightly spaced. The holes will soon increase in size and then the real problem starts. Tomato moth caterpillar don’t just eat the leaves but the toms, too, therefore if you have an infestation you’re bound to lose some fruit.
At this stage, the tiny caterpillar you were looking for on the leaves will have changed into a pretty big critter that’s bigger than your average cabbage white caterpillar by about 50 per cent. Tomato moth caterpillars range in colour from green to light brown, with some even having a ‘go faster’ stripe down the side of their body! The easiest way to spot where they are on the plant is to look out for their poo! They choose a green tomato they like, then they start to hollow it out. The resulting waste, which is pretty big, is normally deposited on the leaf below the fruit in the form of black lumps. It’s easy to remove the caterpillar – they don’t bite or sting – so simply drop it into a container and dispose of as you see fit. Also, unlike cabbage whites, there aren’t normally that many caterpillars on your plants, so keep an eye out now and you should be able to eradicate the problem within two to three inspections. Try planting lots of basil under your plants. The smell can help confuse the moth, meaning
they can’t find the plant and lay their eggs.