Wednesday, July 6, 2016

Spined Soldier Bug

The spined soldier bug (Podisus maculiventris) are a type of predaceous stink bug found all across the United States and in parts of Canada. They can be identified by the distinct "spiny shoulders" on the pronotum. Body is shield-shape and may be brown, or tan, with yellow legs, and a black streak on the wing membrane. They are about 2/3 of an inch long. You will also notice white spots ringed in black along the wing edges. Their common name is derived from the spines on the legs rather than the spiny shoulders. Although I've read a few reports that say otherwise, so I guess it is anyone's guess where the origin of the name really came from.

They are reported to feed on over 50 different species of insects, many of them injurious to crops, garden plants and ornamentals. Their preference for insects such as corn ear-worm, beet army-worm, fall army-worm, cabbage looper, imported cabbage-worm, Colorado potato beetle, velvet-bean caterpillar, Mexican bean beetle,and

eating a green dock beetle
flea beetles makes them a favorite among gardeners and farmers alike. You will often encounter them in a wide range of crops including alfalfa, apples, asparagus, beans, celery, cotton, crucifers, cucurbits, eggplant, potatoes, onions, soybeans, sweet corn and tomatoes. This species is so good at controlling pest insects that it is commonly used as a biological control species within greenhouses.  The use of them in biological programs in colder climates is not met with much success as they do not overwinter and cannot survive freezing temperatures. The use of them in open field biological control programs is met with mixed results. In some cases they remain in the field where they are placed and feed, but there is some indication they are not able to meet the demand and are often outnumbered by pest-prey. In other cases releasing them in your field only results in them taking flight and going to your neighbors field. At this time it is not cost effective to use them on a large scale and unfortunately chemical control seems to be the most cost effective method of meeting the demands of pest control in large operations.

I've often mentioned in other posts that my husband and I quit using insecticides over 20 years ago. Anywhere from 3 to 5 percent of insects that have been sprayed will survive the chemical onslaught. Those individuals will pass a certain amount of resistance onto their offspring. Each subsequent generation passes more and more resistance onto their offspring until you have a "Super-Bug" that is no longer destroyed by the insecticide designed to kill it. Chemical companies are constantly creating new cocktails of chemicals to try and keep one step ahead of the bugs and their resistance. Not to mention that these insecticides do not JUST target harmful insects, they also kill beneficial insects...think honey bees! We've had no problems with pests. We have great success relying on bats, birds, mammals and insect predators in controlling pest insects. We farm over 500 acres without insecticides and I am very proud of this. I wish more farmers would change their use of massive amounts of these harmful chemicals. The stark reality is that the more chemicals they use the more they HAVE to use. They will continue to be held prisoner to the high cost of chemicals until they make that hard decision to stop. At first they will have a complete imbalance of bad insects compared to good insects. Eventually though the ratio will straighten itself out and the good bugs will outnumber the bad ones...not to mention other predators which will also feed on the pest insects. We are proof it works.

These stink bugs have piercing/sucking mouthparts that they use to jab their insect prey and then inject an enzyme which helps dissolve their prey. They use their mouthparts somewhat like a straw and suck out the bodily fluids of their prey. They may also occasionally pierce nearby plants to drink fluids. This does not appear to hurt the plants in anyway, and may actually help keep them around to feed on the insects which do hurt your fruits and vegetables. If all their dietary needs are being met from moisture to meat----there is no need to go anywhere!

These stink bugs overwinter as adults in leaf litter and emerge in the spring when they will mate. After mating, females will begin depositing eggs on the underside of leaves on the plants where they hang out looking for food. A single female is capable of laying up to 500 eggs, depending upon how plentiful food is, as well as how nutritious her food choices were.
Apparently some insects are better choices than others. Mexican Bean Beetles seem to be on the good side of the nutritional scale, whereas Colorado Potato Beetles are on the bad side. In comparison it would be like humans choosing a Big Mac over a salad. It seems there is some indication that if they overeat their lifespan is greatly reduced, compared to those who ate more moderately which seem to live longer. Again....I can see a definite comparison to humans.

I find these stink bug frequently around out farm and can appreciate the beneficial service they are providing in controlling the harmful insects in our garden and our crop fields.

Monday, July 4, 2016

Green June Beetle

Green June Beetles (Cotinis nitida) are scarabs in the family Scarabaeidae and are very common throughout the Eastern United States. You will first begin to see them in June when the larva, or grubs as they are referred to, complete their final moult and emerge as adults. These are fairly large beetles that reach lengths up to 22 mm, or 1 inch. Their loudly buzzing, clumsy flight sounds very much like a bumble bee. Green June Beetles are beautiful scarabs with green metallic wings, edged in gold with bright green legs, head and underside.

Mating takes place during the morning in mid-summer. The female emits a strong-smelling milky pheromone that the male is attracted to and can smell from great distances. Mating lasts several minutes before the male departs and the female disappears into her burrow or under a nearby clump of grass. If mating was successful she will lay up to 75 eggs over the course of 2 weeks. She typically chooses organically rich soil to lay her eggs. The larva, or grubs as they are called, feed on humus and mold early in their development. In their final instar they move closer to the surface of the ground and their feeding habits switch to roots of turf grass, ornamental plants and garden plants. If these beetles occur in large enough numbers their feeding can cause significant damage to grasses, and plants. The grubs pupate in early spring and finish their development by late May or early June when the first of the adults will begin to appear, the peak emergence is in mid to late June.

The adult beetle uses the horn-like projection on their head to tear into soft skinned fruit like peaches, plums, and grapes. They will feed on the flesh of the fruit making it unmarketable for selling. Although the feeding damage caused by late instar grubs is considered more damaging than the feeding habits of the adults. We encounter them once in awhile in our garden, but never in numbers significant enough to cause damage. This could be in large part because we don't use insecticides of any kind. Instead we have a healthy population of birds, bats, and various mammals that all feed on these beetles. Moles will feed on them in the grub stage underground and we certainly seem to have no shortage of moles around here. There is a species of of digger wasp that will burrow into the tunnel of these beetle larva and sting the grub, paralyzing it. Then she will lay and egg on the grub. When the wasp egg hatches it will feed on the paralyzed grub until it is ready to pupate. By not using insecticides or fungicides the beneficial bugs thrive and help control insects that we may not want around. We farm 86 acres where I live and we haven't used insecticides for well over 20 years and I am very proud of that fact. I can say with all honesty we do not have any trouble with crop pests. Often if we will just let nature take care of itself it will do a great job without our interference.

Unlike their brown cousins the June Bugs or May Beetles, which are active at night, Green June Beetle are day active beetles. The one pictured here was found at my work place in the parking lot in the middle of the afternoon.