This weekend I was futzing around in my garden between the rain-showers and well, the bugs have found my vegetable garden. Yup, it is nearly summer and the “bad bugs” are here!
However, not all of the bugs in my garden are bad. For example, the Gulf Fritillaries (Dione (Agraulis) vanillae nigrior) pictured here in a loving – private -- moment.
The Gulf Fritillary is a striking, bright orange medium to large-sized butterfly with a wingspan of from 2.5 to 3.75 inches. Its underwings are buff, with large silvery spots. It takes its name from the fact that migrating flights of these butterflies are sometimes seen over the Gulf of Mexico.
The Gulf Fritillary’s range extends from Argentina through Central America, Mexico, and the West Indies to the southern United States, as far north as the San Francisco Bay Area on the west coast. It is occasionally found further north in the US.
The larva or caterpillar of the Gulf Fritillary grows to approximately 1.5 inches in length and is colored bright orange and covered in rows of black spines on its head and back. The spines are soft to the touch and do not sting. However, the larva are poisonous to birds, lizards and such if eaten. The larva feed exclusively on Maypop Passionflowers (Passiflora incarnata).
Habitat: Open fields and gardens.
Flight: All year.
Adult Preferred Foods: Spanish needle (Bidens pilosa) and lantana (Lantana sp.).
Larvae: On maypops (Passiflora incarnate).
Distribution: All of Florida.
The other good bug I found is the Damsel Bug (Nabis sp.). Adult Damsel Bugs are 3/8 to 1/2-inch long, tan to reddish brown and slender, with the body tapering toward the head. Nymphal stages are similar but lack fully developed wings. Legs are relatively long with the front pair enlarged slightly to capture prey. The head bears long four-segmented antennae and a four-segmented beak (rostrum). The beak is held underneath the body when at rest but is capable of being extended to pierce prey.
Damsel Bugs feed on caterpillar eggs, small larvae, aphids, fleahoppers, lygus bugs, leafhoppers, treehoppers and spider mites, so they are obviously beneficial bugs and should be preserved if you find them in your garden.
Now for the bad bugs… First is the Brown Stink Bug (Euschistus servus). All adult stink bugs are shield shaped. Adult Brown Stink Bugs are shield shaped and dull, grayish-yellow with dark punctures on their backs. Length varies from 1/2 to 3/4 inches for brown stink bug adults.
Brown Stink Bug nymphs develop through five instars that resemble adults but are smaller and oval.
Nymph and adult Brown Stink Bugs pierce plants with their needlelike mouthparts and suck sap from pods, buds, blossoms and seeds. Immature fruit and pods punctured by these bugs become deformed as they develop. Seeds are often flattened and shriveled.
Why, you ask, are they called Stink Bugs? If Stink Bugs are handled or disturbed they give off an offensive odor that drives many potential predators away. The smell comes from a liquid that flows from two glands on the bug’s thorax. Once released, the odor remains on whatever the Stink Bug touches. To most predators, this bug tastes as bad as it smells. Many birds spit out Stink Bugs after biting into them. However, some birds don’t seem to mind the taste.
“The chemicals that make up a stink bug’s stink are called aldehydes, and they are different in different species. In low concentrations, the aldehydes have a pleasant odor. Some of the most common aldehydes in the “stink” of a stinkbug are described by chemists like fine wine: “green, pungent, spicy vegetable odor”, “diffusive orange odor with floral topknots” and “green, citrusy, orange”. But stink bugs concentrate these chemicals so much that they become wholly unpleasant, even irritating. The smell can even kill the stinkbug itself. If the bugs are collected in stoppered vials, or kept in cages without adequate ventilation, the chemicals can get into their respiratory system and asphyxiate them.” Source: Earth & Sky Radio Series
Various sources state that it is difficult to control Stink Bugs because of the way they feed and their hard shells being impervious to pesticides. To control the Stink Bugs on my plants I picked them off with tweezers and drowned them in Isopropyl Alcohol.
The final bug I found on my veggies is the Flea Beetle (Disonycha sp.). These critters come in various colors, but their most distinguishing feature is their huge back legs which allow them to hop away like fleas instead of flying when disturbed. This guy is about 1/8th of an inch long and was photographed in a plastic test-tube.
This particular Flea Beetle was found making holes in my string bean leaves. Diatomaceous earth is one of the more effective Flea Beetle repellents, applied as a dry powder to the plants. Horticultural oils and neem insecticides also have some repellent effect on this insect. Although Flea Beetles are common, injuries often are insignificant to plant health. On established plants, 10 to 20 percent or more of the leaf area must be destroyed before there is any effect on yields. Seedlings are most at risk to Flea Beetle attacks.