The tobacco hornworm (manduca sexta), are often confused with the tomato hornworm (manduca quinquemaculata). These rather large worms can decimate plants of the night shade (solanaceae) family, examples; tomatoes, peppers and egg plants. They also both eat tobacco plants. Both start out as an egg that hatches into a tiny caterpillar that grows and becomes a huge sphinx moth, both can be parasatized by tiny wasps that make cocoons on the worms (cocoons in photo), the wasp larvae feeds on the worm eventually killing the hornworm. Both worms have similar droppings. When I check my nightshade (solanceae) family plants, especially my tomatoes I look on plant foliage for dark green to black droppings which is a good indicator of where to look for the worm, usually near the top of the plant. They blend in really well and they are sometimes hard to locate quickly.
So how do you tell them apart?
The tobacco horn worm (shown in photo), has a red horn and black margins on it's white stripes. The moth of the tobacco hornworm has six orange spots and thick dark bands on the bottom wings, manduca sexta, describes the moths six spots ("sexta" means "six" in latin)
The tomato hornworm has green margins on it's white stripes, a dark blue horn, five orange spots on the moth, and a thin dark band on the bottom wing. Manduca quinquemaculata, describes the moths five spots. "quinque", means "five" and "maculata", means "markings" in latin.
So how do we eradicate them?
The easiest way to eradicate them is knowing how to identify them, as I have described above, then simply find them on the plants and hand pick them off and feed to your yard birds, or put them in a coffee can filled half way with soapy water. The BEST way however, is to create a balanced, healthy ecosystem, which will encourage parasatoid wasps to enter your growing areas and lay their eggs on them, which will eventually destroy the hornworms and increase the beneficial wasps presence in the garden, fields and/or indoor grow spaces.
Host defenses can occur, for example, some insects secrete poisonous compounds that kill or drive away the parasatoids. Ants that are in a symbiotic relationship with caterpillars, aphids or scale insects may protect them from attacks by wasps. I have witnessed both red ants and aphids doing this very thing on a patch of my kale plants with cabbage worms. The parasatoid wasps are winning the war however, as I have noticed and documented more cocoons and a significant decrease in caterpillars and damage to foliage. Please understand that I do not use ANY harmful herbicides or pesticides of any kind on my farm. My goal is to balance the immediate ecosystem through natural balance of both the beneficial insects and the non-beneficial.
Like any ecosystem, gardens involve an intricate web of life, from the soil microbes, (we can not see) that live beneath the ground, to the birds we see in the tress and everything in between. It's easy to grab a bottle of spray to kill the dandelions or knock off the aphids or other pests eating the plants, but what are we really doing when we do this? We are essentially creating a domino effect of destruction to our environment, are we not?
Use of chemicals disrupts the food chain of the weeds, plants and animals. Many of these weeds, plants and animals, we may think of as the bad guys are essentially providing services that we often can't comprehend, or even begin to understand.
Many species of flies and wasps are actually pollinators as adults, and as larvae they help control many of the pests on our plants and/or decompose organic matter. Small reptiles, like lizards and geckos eat garden pests, like mosquitoes, crickets, caterpillars, moths, grasshoppers and slugs.
Plants that are often looked at as weeds have benefits too. Clovers and dandelions provide flowers for ladybugs, hover flies and bees. Clover has the ability to transfer airborne nitrogen into the soil to be used by neighboring crops. It is also a nutrient accumulator, it accumulates phosphorus. It also makes an excellent egg laying site for beneficial lacewings. Did you know the flowers of clover are edible? Clover as many useful benefits in the garden or fields.
Dandelion (Taraxacum Offinale) One of the most beneficial of ALL weeds. Nutrient accumulator, accumulates potassium, phosphorus, calcium, copper, magnesium and more, while loosening soil. Attracts numerous pollinators. Dandelions are edible, the entire plant can be used, the flowers medicinally. I allow both clover and dandelion to grow in and around my farm as part of my whole system no till farming approach. The less we disturb the soil, insects and the plants, the healthier the immediate ecosystem.
Whole system farming and thinking is the ability to see the interrelationships of all living things, rather than all living things as individual or separate. It is a focus of looking at patterns of change, rather than static pieces. All living things are interconnected with one another. If we disrupt a negative, we can create two negatives. If we allow a healthy balance, we create harmony.
"You can't solve problems with the same thinking that created those problems" - Albert Einstein