Extension Educator, Local Food Systems and Small Farms
Extension Educator, Horticulture
July 26, 2011
Large, shiny, green beetles have appeared, and many think they have bumblebees because of the buzzing sound they make when they fly. These beetles are much larger than either June bugs or Japanese beetles.
Green June Bugs are also called fig eaters. This is because they can eat soft fleshed fruits such as grapes, plums, peaches, and apricots. In their larval stage they are a grub, but don't do a lot of turf damage like the normal June bug. They tend to be in high organic matter places such as flower beds, gardens, compost piles, and under shrubs, so the grubs aren't turf pests.
As for control, there is probably none necessary unless you need to protect those soft fleshed fruits. Then you should follow the recommended spray program so you don't cause problems with the fruit later on. The Green June Bug doesn't sting or bite, so you can put them in the nuisance pest category. The main damage they can do is fly into you, and that can hurt. On the bright side, you are probably already protecting things of value from the Japanese beetles, so you may be covered.
July 26, 2011
The cicada killer wasp has returned. They are actually considered beneficial insects because they control cicadas and katydids. This wasp gets its common name due to the fact that it hunts and supplies its nest chambers with a cicada, which becomes a food source for the young wasp. Cicada killers are a nuisance pest, especially when nesting in large numbers in a play area or near the house. People get concerned because the cicada killers resemble giant yellowjackets.
Cicada killers are about 2 inches long and black to red, with yellow banded markings on the abdomen. The head and transparent wings are reddish brown. They are not dangerous, but they are intimidating. Cicada killers are solitary wasps, with the female digging a 6- to 10-inch burrow (1/2 inch in diameter) in the ground. A pile of soil typically surrounds the entrance. The female locates and stings a large insect such as a cicada or katydid and then brings it back to the burrow. She places the insect into a chamber and lays an egg on it; sometimes she puts two in a burrow but lays an egg on only one. She then covers the burrow, digs another, and repeats the process. The egg hatches into a grublike, legless larva that consumes the paralyzed insect. Full-grown larvae overwinter in the burrow, pupate in the spring, and emerge as an adult during the summer, usually in July and August.
Cicada killers are unlikely to sting a person. Wasp and bee stingers are modified egg-laying devices (ovipositors), so males are not able to sting. Females may sting if crushed, either by being stepped on with bare feet or grabbed with bare hands.
Cicada killers are more common in areas with bare soil, so mulching, planting ground covers, or putting down sod can reduce problems. Applying permethrin, bifenthrin, or Sevin (some suggest the Sevin dust gives better control) to the burrowed area should kill females in high traffic areas. Once females are gone, males leave. In home yards, sandboxes can be covered with a tarp when not in use, as this deters the wasps (and also keep cats out). Sand below swings, jungle gyms, or other playground equipment is a popular site for the cicada killer. Raking the sand may discourage the wasps, or you could use mulch instead of the sand. In extreme nuisance situations, treatment of burrowing areas with a pyrethroid insecticide or carbaryl may reduce problems.
July 26, 2011
July 26, 2011
Many tomatoes are suffering from blossom end rot, where there is a leathery rot opposite the stem end. This is a calcium imbalance in the plant, usually caused by uneven moisture conditions. Mulching and watering once a week help. If you have container tomatoes, the problem is much harder to solve. Things should even out on their own for soil grown tomatoes.
July 22, 2011
We have discussed the timing of grub control treatments in past columns. As a reminder, the date would have been early August for annual white grubs. Treatment times for Japanese beetle grubs should probably be late August this year. Knowing when to treat grubs is one thing, and knowing what product to use is another.
Many grub control treatments are combined with fertilizer products, and this is the appropriate time to apply a fall fertilizer treatment. It seems each year provides more "stand alone" treatment options as well. Diazinon used to be the product of choice for many homeowners, but the cancellation of home horticulture uses of the product created confusion in selecting a product. The other wild card was the use of diazinon helped eliminate mole problems (by driving them to the neighbor's yard) since the product killed grubs and reduced earthworm populations. Many of the products currently used do not affect earthworm populations, and on the whole that is a good thing since earthworms greatly benefit lawns. There are now some "soft baits" available for mole control that are effective.
Current recommended products include halofenozide (Mach 2), Heterorhabditis bacteriophora (Cruiser), imidacloprid (Merit), and trichlorfon (Dylox). Many of the chemicals have other brand names in addition to the ones listed in parenthesis. It is also recommended to drench treated areas with a half inch of water within 30 minutes of application, and this is especially important with liquid applications. Application just ahead of a rain is usually best. Granular applications buy a few days of time, but still need to be watered into the root zone where grubs are active. The products with Merit will take three weeks or so to activate. Some reputable sources also list carbaryl (Sevin) granules as an option for grubs from green June bugs and Japanese beetles. Carbaryl does reduce earthworm populations to some degree.
In good growing seasons, it normally takes at least 10 grubs per square foot of lawn area to justify treatment. In less favorable seasons, this number can be reduced to six to eight grubs per square foot. As your gasoline bill for the lawn mower can attest, this has been a good growing season to date.
Consider many factors when selecting a product. These would include combination with fertilizer, effectiveness, species controlled, cost, and the effect on the environment. The Cruiser product is actually a nematode, and would be the most environmentally safe. It also costs about $55 to treat about 3000 square foot of lawn. The other organic product sometimes mentioned for control of the Japanese beetle grubs is milky spore. This product is a bacteria which takes several years to become very effective and can cost around $35 for 2500 square foot of lawn. You can't apply any other controls with milky spore since you need high populations of grubs to increase the bacteria populations to high levels and provide transmission between grubs.
Good luck as you decide your attack plans against grubs. The choices are many, and the attainment of the "perfect" lawn is a goal many strive for. Remember, you can live with some grubs. However, too many can be devastating to a lawn. With Japanese beetle populations at very high levels in many areas, odds are great there will be grubs to battle.
July 22, 2011
Insect of the week honors go to the rather inconspicuous potato leafhopper. This is the small wedge-shaped, light green insect that seems to just fog around security and patio lights. They are also small enough to come in through screens after dark. They are not only a nuisance, but they can cause damage to a wide variety of plants.
Potatoes are the first plant that comes to mind when we talk about potato leafhoppers (must be something about the name), but many other plants ranging from beans to trees can be affected. You may be wondering what kind of damage a few little leafhoppers can do, especially since they suck sap from plants and aren't that big in size.
Leafhoppers suck sap and then inject a toxin back into the plant. Along the same lines as humans getting a mosquito bite - it's the extra that's injected back in that causes the injury. Symptoms of leafhopper damage start as yellow "v" shaped areas on the tips of leaves. These areas turn brown or black and then fall out leaving a "v" shaped hole on the tip of the leaf. This is a symptom, but not the only injury. Large numbers of leafhoppers can kill potato and other plants.
Controls for leafhoppers are warranted with very low numbers. In alfalfa fields, it is recommended to treat when 2 leafhoppers are caught in a sweep net in alfalfa over a foot tall. Garden treatment options for potatoes include Sevin, bifenthrin, permethrin, and rotenone as common insecticide choices available to homeowners. Most trees and shrubs can be treated with Sevin, permethrin, or bifenthrin.
July 22, 2011
The weather we have been experiencing has made rust a problem for many homeowners in their lawns again. As grass growth slows, rust will be one of the lawn fungi we are dealing with. Rust appears as an orange or yellowish-orange powder (spores) on grass leaf blades, especially in late summer to early fall when the weather is dry. Rust typically develops on lawns growing very slowly. Overall, the turf may assume a yellow, red, or brown appearance. Close examination will reveal the pustules, which easily rub off on your hand. Rust spores can easily be tracked into homes.
Low fertility (in particular nitrogen) and low water availability slow down turf growth, allowing rust to develop. Seasons with excess rain may have rust outbreaks due to loss of available nitrogen. Cool nights with heavy dew and light, frequent rainfall add to the ideal conditions for rust to develop. Warm, cloudy, humid weather followed by hot, sunny weather also favors rust development on lawns. Kentucky bluegrass, perennial ryegrass, and tall fescue are all affected, depending on cultivars. Rust spreads through air, water, shoes, equipment, and sod. Rust may weaken turfgrasses and make them more susceptible to other problems.
Control rust through sound turf management. Begin by choosing a quality blend of turfgrass seed. Resistance to rust can vary according to the race of the disease present. Maintain lawns through sound watering, mowing, and fertilizing. If you are watering, water early in the day so the grass dries quickly. Manage problem thatch. Increase vigor with an early fall nitrogen application, but don't overdo it. Check soil phosphorus and potassium levels through soil testing. Also assure good airflow over the site and light penetration by pruning trees and shrubs in the area near the lawn.
When rust occurs at this time, improved growth conditions of early fall often get lawns growing more vigorously and the rust fades away. Early September is a key time for fertilization. If conditions are dry, irrigation is also needed to increase the growth rate of the lawn.
Fungicides are rarely suggested on home lawns for rust control. Focus on the listed cultural practices described above.
July 22, 2011
July 7, 2011
People are beginning to complain about leaking sap coming from trees. Actually this has been going on for a week or so. What happens is a fine mist of sap coats things beneath a tree. This is actually called "honeydew," which is a secretion of sucking insects such as aphids and lacebugs. What makes matters worse is a fungus begins growing in the honeydew, making it turn black.
There are two ways to deal with the problem. The first way is to spray the entire tree with a product, such as malathion, to kill the insects. The second way is to move anything portable from under the tree. If you opt for the first option, you need to make sure you can spray the entire tree. The kind of weather predicted will increase aphid numbers at a very great rate.
July 7, 2011
Cucurbits are basically everything in the squash and melon families. There are several potential insect problems with them, and today's column attempts to help minimize or prevent these problems. The first group of insects is the cucumber beetles. These can be green, black and yellow striped, or black and yellow spotted. These are also called corn rootworm beetles when they are in corn fields. When these insects are in cucurbits, they are usually called cucumber beetles. The importance of the beetles is not that they eat small holes in the leaves, but that the striped and spotted beetles can transmit a bacterial wilt to the plants as they eat. The first thing you see is you have a plant that suddenly wilts on various runners, or the entire plant. The best means of controlling this disease is a good beetle control program. Current homeowner recommendations would include these products with the days to harvest restrictions in parenthesis: carbaryl (0), bifenthrin (3 days), or rotenone (1 day).
Of course, Japanese beetles love cucurbits as well. Their damage is direct leaf feeding. Remember they feed in groups, so once they get started you will have a battle on your hands. The carbaryl and bifenthrin are both good control measures.
Squash bugs are the next problem to discuss. Squash bugs are usually dark gray to black in color and like a long stink bug. Their eggs usually hatch mid-June to mid-July. Best control timing is when the eggs first hatch. Non-restricted products are sabadilla (1 day), which is an organic product that might be a little hard to find, and bifenthrin (3 days to harvest). One last note, if the squash bugs get past their early growth stages then physically removing them is about the only control method available.
The last insect problem on cucurbits is squash vine borers. These borers usually drill into the new runner areas and kill off individual runners at a time. The adult of these larvae are red and black clear-winged moths. Scout your plants and look for the adults, as well as entrance holes and the chewed-up plant material. Treat as soon as early damage occurs and use one of the following products for homeowners: carbaryl, bifenthrin, or rotenone. Days to harvest restrictions have already been covered (and these would also apply to pumpkin blossoms).
July 7, 2011
If you haven't checked for bagworms yet, now would be a good time. I've seen some this year of ¾ inch bag size. Re-treatment may be necessary in some cases. Sevin will work on the smaller sized bagworms, while the B.t. products may be required for the larger ones.
Remember bagworms frequently start in the tops of trees. Bagworms are the larvae of clearwing moths that don't fly too well. If you control the bagworms well, you may not have high populations for a few years.