Tomato Troubles – Fruitworms

Nothing beats a fresh tomato straight from the garden. Maybe that’s why it is so disappointing when you are ready to harvest a few, only to find some critters have beat you to the prize. The tomato fruitworm, shown below, is one pest that you may be seeing in your garden now.


Photo: Leanna Murphy Dono

Also known as the corn earworm or cotton bollworm, these larvae of the Helicoverpa zea moth enter tomato fruits near the stem end, feeding on the fruit and providing an entry point for decay-causing microorganisms. This pest can also damage leaves and stems of tomato plants, as well as peppers, beans, corn, broccoli, cabbage, okra, soybeans, and tobacco.

The H. zea moth is “usually light yellowish-olive with a single dark spot near the center of each forewing. It lays eggs singly, usually on the lower sides of leaflets close to the flower or fruits. The eggs are creamy white when laid but develop a reddish-brown band just prior to hatching. Larvae (caterpillars) hatch from the eggs. The larvae are yellowish-white with a brown head. The color of older larvae varies from greenish-yellow to brown or even black with paler stripes running lengthwise on the body. Larvae grow to a size of about 1½ inches in length”. (per Clemson University HGIC 2218) Fruitworms overwinter in soil and emerge in May – June. Moths are commonly seen at night during summer and early fall.


Life Cycle Photo:

Bacillus thuringiensis (B.t.) products are the recommended control for fruitworms in the home garden.

Creepy Crawly Creatures

I’ve seen a lot of creepy crawly caterpillar-like creatures this week. Here are two you may have noticed.

Hornworms If you grow tomatoes, you have probably dealt with hornworms. These large, lime green larvae can do some serious damage to tomato plants and fruits. They also feed on tobacco, potato, eggplant, and pepper plants.


Since hornworms are large, it is easy (but perhaps time consuming) to check your tomato plants daily and remove the hornworms by hand. If you would prefer to use an insecticide, organic and synthetic formulations are available. For examples of these, please see

If you find a hornworm that looks like this one,hornworm

Good News – for you, not the hornworm. This hornworm has been attacked by parasitic wasps. The young feed on the hornworm and will eventually hatch and search for more hornworms on which to lay their eggs. Leave parasitized hornworms on your plants for natural pest control.

The adult is known as a sphinx moth, which looks like this

sphinx moth

For more information on hornworms, see This link has more fantastic photos: Photos from except adult sphinx moth, from

Orangestriped Oakworm

In August and September, you may notice these caterpillars on the ground.


If you have an oak tree, particularly a willow oak or pin oak, you may also notice damage like this. Leaves of this oak have been stripped except for their midribs.

oakworm damage

The oakworm moth (seen here) lays eggs on the undersides of leaves in June and July. Young caterpillars are green in color, but change to black with orange stripes as they grow. Once they are mature, they drop to the ground to find an underground spot to pupate. In late August/early September, they can be a common sight on sidewalks and streets.

Since damage occurs late in the season, control is usually not necessary. Trees can generally recover from damage when it happens in late summer or early fall. If you wish to use a chemical control, options can be found here: Please note that it is probably too late to control this year’s population and that spraying large trees can be difficult and costly.

-Ann Barnes

While the Gardener is Away…

While the gardener is away (and/or doing indoor projects while we’ve been inundated with rain)… pests will play!

I normally scout for pests two or three times per week (sometimes more), the downpours, mud, holiday, and a family trip kept me away from my veggies lately. When I stepped into the garden yesterday, I found that my brussels sprouts and kale had been overrun by caterpillars. This is a good reminder of why scouting regularly is important!



There are many different caterpillars that attack plants in the cabbage family. My plants were full of cross striped cabbageworms, but cabbage loopers, diamond back moths, and imported cabbage worms can also be a problem. Check the undersides of leaves to find the caterpillars and eggs.

If you want to know which pests are eating your veggies, see these links:

eggssmall larvae, cross striped cabbagewormpupae, moths

You can remove the insects by hand, but if you have a large infestation, chemical control may be required. Organic choices include Bt (Bacillus thuringiensis) and spinosad. Synthetic insecticides include the active ingredients permethrin, bifenthrin, cyfluthrin, or esfenvalerate. As with all chemicals, please read the label thoroughly before applying.

Source material:,

What’s Eating my Plant?

A few days ago, while I was watering the potted herbs on my desk, I spotted the following critters munching on some fennel.



Most of the time, I’m not pleased to find caterpillars making a meal of my plants, but these are swallowtail caterpillars. In fact, I planted the fennel in the hope of feeding these guys. A few years ago, I enlarged a nearby flower garden, focusing on plants that attract butterflies. When I started seeing lots of swallowtails, I decided that I should feed the caterpillars as well as the adults.

Six days later, the 4 caterpillars had munched on quite a bit of my fennel plant, so I headed for the garden center to buy three more. I hope there’s enough food to keep them around until it’s time for metamorphosis.


If you are interested in attracting butterflies to your yard, this website lists plants that provide food for caterpillars and nectar for the adult butterflies.