“WHAT’S HAPPENING?”

The University of Tennessee/Agricultural Extension Service

Entomology & Plant Pathology - EPP #60

Volume No.5 - April 30, 2004

SUDDEN OAK DEATH FACTSHEET AND MORE

by Darrell Hensley

Sudden Oak Death has more hosts other than oak trees. Others include: Douglas fir, coastal redwood, Lonicera, Rubus, Pittosporum undulatum, Acer macrophyllum, elderberry, and others.

Newly planted azaleas, rhododendrons, and camellias may be host to a deadly fungal disease that has killed thousands of oak trees in California, according to the U.S. Department of Agriculture.

The plants were imported from Monrovia Nurseries in California before it was determined they carried the fungal disease that causes sudden oak death. When The U.S. Department of Agriculture alerted state officials in

Tennessee, Georgia and elsewhere, imports were stopped, nurseries were visited and samples were collected, officials said. Deep Springs Nurseries in Dalton is among thirteen nurseries in Georgia identified by the state

Department of Agriculture as having plants that tested positive for the disease, which has no known cure and cannot be eradicated with fungicide. Tennessee regulatory officials reported two sites in the state tested

positive for the disease. These sites are located in Shelby and Bradley counties.

Please visit:

http://www.cnr.berkeley.edu/garbelotto/english/factsheet.php

For more information concerning SOD.

ACTIGARD LABEL CHANGES

by Darrell Hensley

Actigard plant activator manufactured by Syngenta has some new label changes for burley tobacco.

The changes include up to three applications may be made on a 10-day schedule. Also, another registered blue mold protection product should be used prior to the plant reaching 18 inches in height for early season blue mold control. After final application of Actigard, if conditions are conducive for disease development, other products may be needed. Reminder : Do not apply to tobacco less than 18 inches in height. Apply Actigard in a

minimum of 20 gallons of water per acre.

CARPENTER BEES SEEN PATROLLING STRUCTURES

by Karen M. Vail

Carpenter bees have been very active and residents have been alarmed by these large bees flying near eaves. Quite often it is the male carpenter bee that is seen patrolling the area and they are unable to sting. The females are not aggressive, but may bite and sting if handled. Males are easily distinguished from females by a large white marking on their “face”. So if you want to impress someone, reach up and grab one of those males hovering in your face.

Carpenter bees are large bees and are similar in appearance to bumble bees, except the dorsal (top) surface of the abdomen is almost devoid of hairs and appears to be entirely black in the carpenter bee. Also, don’t confuse the white-faced male carpenter bee with a bald-faced hornet which also has a white “face”. You’re most likely to encounter a female bald-faced hornet and she is not forgiving. Catching this female in your hand may cause her to sting, release an alarm pheromone and recruit hundreds of other nest mates - all with stingers.

While carpenter bees are pollinators for several species of plants such as may pop, they are considered pests when they bore into wood. Bare, unpainted, weathered softwoods, especially redwood, cedar, cypress and pine, are preferred. Painted or pressure-treated wood is less likely to be attacked. Some common nest sites include eaves, fascia boards, siding, wooden shake roofs, decks and outdoor furniture. A gallery for brood is excavated in weathered and usually unpainted wood and the exit hole is a nearly perfect circular hole about ½" in diameter. These holes often appear as if they were made by a drill bit. The gallery initially extends straight from the opening, but soon makes a right angle turn to go with the grain of the wood. In the gallery the female lays an egg, provisions it with nectar and pollen and seals the cell with chewed wood pulp. Galleries may contain six cells and are four to six inches long on average. However, because the galleries are reused and may be used by more than one bee, lengths of up to 10 feet have been reported. The new adults will appear in late summer.

Nonchemical or preventive controls include painting wood surfaces. Individual bees can be caught with a net and killed or swatted with a badminton racket. Also, a flexible wire can be inserted into the hole to kill adult and larval bees, but the wire needs to be strong enough to break the wooden cells and flexible enough to make the right angle turn.

Insecticidal dusts (Tempo 1D, DeltaDust, Zep Pest Termite and Ant Killer) can be puffed into nest holes in the evening when the carpenter bees are at rest. An insecticidal dust fills the void very well and will not soak into the wood as a liquid might. The bees should have access to the nest for at least 24 hours to allow them to spread the dust through the galleries. The hole is then sealed with a wooden dowel coated with suitable sealants, such as carpenter’s glue or wood putty, to prevent reinfestation, moisture intrusion and wood decay. Carpenter bees overwinter in previously used galleries, so the structure should also be inspected in the fall and any holes that may have formed should be treated and sealed.

In the past, many fact sheets referred to the use of Sevin (carbaryl) for control of carpenter bees; however, I have not been able to locate a Sevin label that listed wood as a use site. Ficam dust (bendiocarb) is very effective in controlling carpenter bees, but it has been voluntarily withdrawn from the market. Existing stocks can still be used.

Homeowners may not have access to insecticidal dusts labeled for wood treatment and thus may need to apply sprays (Bee/wasp killer aerosols, Ortho Termite and Carpenter Ant Killer [bifenthrin], Bayer Advanced Home Pest Control Indoor and Outdoor Insect Killer ready-to-use pump [cyfluthrin] or others) into the nest opening.

According to Mike Potter, University of Kentucky, a broadcast insecticidal spray onto wood surfaces attracting large numbers of bees may be needed as a deterrent. A broadcast spray, such as Bayer Advanced Powerforce Carpenter Ant and Termite Killer Plus Concentrate [β-cyfluthrin], Ortho Home Defense System/Termite & Carpenter Ant Killer [bifenthrin], or others), is often warranted when carpenter bees are riddling large areas of wood such as siding on a barn, wood shake roofs, or decking. A broadcast treatment is best accomplished with a pump up or hose end sprayer that targets the wood surfaces that are most favored by the bees (fascia boards, joist ends of redwood decks, etc.). Residual effectiveness of deterrent surface applications is only about 1-3 weeks, so the treatment may need to be repeated.

A few years ago, we were conducting carpenter bee research with the representatives from a local pesticide manufacturer and we needed to exclude the bees from currently occupied galleries in the fascia boards. On a warm sunny day in which we hoped all the bees would be foraging outside of the nest, the gallery openings in fascia board were stapled or nailed closed with gutter guard. Many bees became trapped behind the guard. Some were killed when attempting to forage, but many others from the next generation (last summer) were also trapped. Now, the gutter guards are not aesthetically pleasing. I believe they are a light, flexible, “woven” metal or plastic. An oil-based paint may provide some protection; however, if your fascia can be painted, why not apply the gutter guard and paint over it? No one will know it’s there, except the bees.

Sources:

Potter, M. 2003.Managing Carpenter Bees. KENTUCKY PEST NEWS. Number 982, Kentucky Cooperative Extension Service. 04/21/03 www.uky.edu/Agriculture/kpn/kpnhome.htm

DISEASE OF VINE CROPS

by Darrell Hensley

US plant pathologists are reporting a significant increase in the occurrence of Phytophthora blight of vine crops (cucumbers, pumpkins, pumpkins, and squash, in many vegetable-growing regions of the United States. This devastating disease, caused by the soilborne fungus, Phytophthora capsici[Pc], often results in nearly total yield loss.

According to a professor at the University of Illinois, this blight has become one of the most serious threats to production of vine crops, or cucurbits, in the US and worldwide. Recent outbreaks of the blight have threatened pumpkin and other cucurbit industries especially in Illinois, which produces about 90 per cent of processing

pumpkins grown in the US. Heavy crop losses often force growers to abandon their own farms, and move into different areas, sometimes traveling more than 50 miles, to find fields free of the disease.

The blight can strike cucurbit plants at any stage of growth. Infection usually appears first in low areas of fields where the soil remains wet for longer periods of time. The pathogen infects seedlings, vines, leaves, and fruit.

The disease is usually associated with heavy rainfall, excessive irrigation, or poorly drained soil. Frequent irrigation increases disease incidence.

Currently, there are no cucurbit cultivars with measurable resistance to the blight. Plant pathologists are working to find new methods of controlling the disease. Babadoost says that in addition to exploring

cultural management strategies, plant pathologists are assessing the possibilities of biocontrol agents, fungicides for control of the pathogen in cucurbits and other crops as well as using induced resistance in plants.

Disclaimer Statement

Pesticides recommended in this publication were registered for the prescribed uses when printed. Pesticide regulations are continuously reviewed.

Should registration or a recommended pesticide be canceled, it would no longer be recommended by

The University of Tennessee.

Use of trade or brand names in this publication is for clarity and information; it does not imply approval of the product to the exclusion of others that may be of similar, suitable composition, nor does it guarantee or warrant the standard of the product.

The Agricultural Extension Service offers its programs to all eligible persons regardless of race, color, age, national origin, sex, veteran status, religion or disability and is an Equal Opportunity Employer.

COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS

The University of Tennessee Institute of Agriculture, U.S. Department of Agriculture,

and county governments cooperating in furtherance of Acts of May 8 and June 30, 1914.

Agricultural Extension Service Charles L. Norman, Dean