PANTRY PESTS continue to be the most common insects found in homes during the winter months.
The Kentucky Department of Agriculture Division of Environmental Services has mailed out license renewal forms. The form must be signed and returned to this office with the appropriate fees. Non-commercial license holders, employees of government, golf courses, public utilities, and universities do not have to pay any fees but the renewal form must be returned. If you need to talk to someone regarding your renewal, please call (502) 573-0282 or (866) 289-0001.
Properly cleaning your sprayer this fall can save you time and headaches next spring. Cleaning a sprayer regularly can prevent unnecessary and costly repairs, and cleaning it before winter storage increases its life. While properly cleaning a sprayer for winter storage is important, it is also required throughout the spraying season. Thoroughly cleaning your sprayer can prevent injury to nontarget vegetation that is susceptible to a previously applied pesticide. This is especially critical if you are going to switch the type of herbicide being applied, or switch from making herbicide applications to making insecticide or fungicide applications.
Spray contamination caused by a failure to thoroughly clean a sprayer can cause crop injury up to several months after using the sprayer, and following several subsequent applications. This can occur when herbicide residues that adhered to a surface within the sprayer are brought back into the spray solution via a subsequent herbicide or adjuvant that acts as a solvent on the herbicide residue. Plant-growth-regulator (PGR) herbicides in particular are difficult to clean from a sprayer. Other herbicides, glyphosate being one of them, are effective at dissolving PGR herbicide residues in a sprayer. This can obviously cause severe problems if the sprayer is used to make applications of glyphosate on crops sensitive to the PGR herbicide dissolved in the sprayer. Rinsing with water alone does not remove PGR herbicide residues.
The pesticide label for the product you have been applying and your sprayer manual are two important sources of information on how to properly clean the sprayer. It is especially important always to check the label for special cleaning instructions and warnings related to sensitive crops that would be affected by tank contamination. When cleaning a sprayer, remember to wear the same personal protective equipment as required when making an application with the pesticide being cleaned out of the sprayer.
Leaving the spray solution in the sprayer for longer periods of time increases the risk of contamination due to the increase in difficulty of removing dried pesticides, compared to pesticides that are still in solution. For this reason, it is recommended not to allow herbicide mixtures to dry in the sprayer. Some pesticides can cause the equipment to deteriorate if they remain in the sprayer for an extended period. Clean a sprayer as soon as possible after use. If possible, plan on always ending the day with an empty spray tank. Even if you plan to spray the same pesticide the next day, flush the tank with clean water after spraying. Some pesticide solutions may create a pastelike substance in the tank, and rinsing out the sprayer at the end of each day or even after every load can help prevent an accumulation.
Many sprayers have built-in rinse tanks that hold sufficient water to allow rinsing the main solution tank three times immediately following an application. Sprayers with rinse tanks generally also have tank-rinse nozzles designed to provide complete spray coverage of the inside of the tank. Rinse tanks and nozzles make rinsing out a spray tank after an application easier, quicker, and safer. If possible, apply the rinsate on the treated application site in a manner consistent with the label. Repeatedly rinsing a sprayer with small quantities of water is more effective than a single rinsing with a large quantity of water, provided all sprayer parts can be reached with the smaller quantity of water.
In general, plastic and polyethylene tanks require a more thorough cleaning than stainless steel tanks. Inadequate agitation can allow dry-flowable and wettable-powder formulations to build up accumulations in the bottom of spray tanks. The upper surfaces of the tank and surfaces around the tank baffles can be difficult to clean well. However, do not focus only on the tank when cleaning. Pesticide residues on hoses, sumps, strainers, pump surfaces, and other sprayer components can also cause contamination if not removed during cleaning. Cracks in hoses often accumulate pesticide residues and are difficult to clean. Worn hoses should be replaced to reduce the risk of this occurring.
Check and clean strainers daily. They can be a source of contamination, and partially plugged strainers create a pressure drop and reduce the nozzle flow rate. Most sprayers have up to three different strainers: one on the suction hose to protect the pump; another in the line between the pump and the boom; and a third, which has the smallest openings, in the nozzle body.
Cleaning agents can work to dilute or deactivate pesticide residues, but many cleaning agents work by increasing the solubility of the pesticide. These cleaning agents dissolve the pesticide residue in the rinse solution, which can then be flushed from the sprayer, removing the residue. As an example, ammonia is the recommended cleaning agent for removing sulfonylurea herbicides from sprayers. An ammonia solution increases the pH, which increases the solubility of sulfonylurea herbicides. The ammonia, however, does not decompose or deactivate the herbicides. Although a chlorine bleach solution decomposes sulfonylurea and other types of herbicides, it is not as effective as ammonia at dissolving sulfonylurea herbicides, and therefore does not work as well for removing these herbicide residues from sprayers. Never mix chlorine bleach with ammonia or liquid fertilizers that con-tain ammonia: The chlorine and ammonia react and form chlorine gas, which is toxic and can cause eye, nose, throat, and lung irritation.
When cleaning the sprayer, use only water that appears clean enough to drink. Water from ditches, ponds, or lakes can contain small particles that can clog nozzles and strainers. The type of cleaning agent you use to clean your sprayer depends on the type of pesticide formulation used. Residues from some formulations are more difficult to remove from the tank than others. To remove residues of oil-based herbicides, such as esters of 2,4-D and similar materials, fill the tank one-quarter to one-half full with a water-ammonia solution (1 quart of household ammonia to 25 gallons of water) or a water-trisodium phosphate (TSP) solution (1 cup of TSP to 25 gallons of water). Circulate the solution through the system for several minutes, allowing a small amount to pass through the nozzles. Let the remainder of the solution stand at least 6 hours, and then pump it through the nozzles and drain the tank. Remove the nozzles and strainers, and flush the entire spray system twice with clean water, making sure to remove all pesticide-contaminated rinsate from the spray system. Oil-based solvents, such as fuel oil, are also effective at removing oil soluble pesticides. After cleaning with an oil-based solvent, rinse the sprayer with a detergent solution to remove oil residues, followed by two clean water rinses.
Equipment in which wettable powders, amine forms, or water-soluble liquids have been used should be thoroughly rinsed with a water-detergent solution (2 pounds of detergent to 30 to 40 gallons of water). Water-soluble materials should be treated as water-soluble liquids. Allow the water-detergent solution to circulate through the system for several minutes. Remove the nozzles and strainers, and flush the entire spray system twice with clean water. Commercial cleaning agents are available, and many of these can be used to remove residues of both water- and oil-soluble pesticides. The commercial cleaning agents tend to work better than household cleaning agents and can serve both to dissolve and to deactivate pesticide residues.
Remove nozzle tips and screens, and clean them using a cleaning solution. Use a brush with plastic bristles to clean the nozzle tips. Rinse the cleaning solution off all parts with clean water. Many nozzle manufacturers have brushes designed specifically for cleaning out nozzles. Never use a metal object for cleaning nozzles. Metal objects destroy the orifice, which can alter nozzle flow rate, spray pattern, and droplet size. When a nozzle becomes clogged, always remove it for cleaning.
Activated carbon can also be used to clean out a sprayer. It works by deactivating, or tying up, certain organic pesticides. A solution of 3 percent activated carbon in water can be circulated through all of the sprayer components. Afterward, rinse the sprayer thoroughly with water to remove all the activated carbon, as any remaining traces of activated carbon will deactivate a portion of the next pesticide applied with the sprayer. It is important to note, however, that activated carbon is quite abrasive and can potentially damage certain spray equipment, particularly roller-type pumps. To avoid damage, be sure to read and follow all label directions.
When it is time to store your sprayer, add 1 to 5 gallons of lightweight oil, depending on the size of your tank, before the final flushing. As water is pumped from the sprayer, the oil leaves a protective coating inside the tank, pump, and plumbing. To pre-vent corrosion, remove the nozzle tips and strainers, dry them, and store those that are corrosion prone in a can of light oil, such as diesel fuel or kerosene.
When it comes to plant disease information, our plant pathology group, like other units associated with the U.K. Cooperative Extension Service, are dedicated to providing science-based educational information on plant disease management. To that end, Extension Specialists and County Extension Agents sometimes need to have access to the original publications of experimental results. For plant diseases, the Plant Management Network is a good source of detailed science-based plant disease information accessible to U.K. employees.
U.K. Extension Specialists, County Extension Agents, and all other College of Agriculture employees have access to the Plant Management Network (http://www.plantmanagementnetwork.org/), thanks to a college-wide subscription provided by the Kentucky Integrated Pest Management Program.
In the area of fruit crop diseases, for example, recent articles dealing with diseases of Kentucky fruit crops have been published in resources such as B&C Tests and F&N Tests, (now Plant Disease Management Tests) or in the journal Plant Health Progress. Plant disease management tests published in a given year typically are the results of field research done the previous year. The lists that follow are representative of scores of report titles that can be found on the Plant Management Network site.
Selected examples of recent fruit crop disease management reports from B&C Tests include:
Selected Plant Health Progress journal articles relating to fruit diseases include:
U.K. Extension Specialists, County Extension Agents, and all other College of Agriculture employees have
access to the Plant Management Network
(http://www.plantmanagementnetwork.org/), thanks to a college-wide subscription provided by the Kentucky Integrated Pest Management Program.
Phytophthora ramorum is a quarantine plant pathogen for the state of Kentucky, it has a broad host range and is considered to be a problem in nurseries and forested areas including urban areas like parks and landscaped areas. The host range includes woody trees and shrubs, herbaceous plants and ferns, and the disease symptoms vary with the host type: sudden oak death is seen only on oak and tanoak trees, and Ramorum blight diseases develop on other plants. On plants like rhododendron, camellia and viburnum leaf and twig symptoms such as brown lesions and blotches on the leaves, necrosis of the leaf tips and leaf blight are typical symptoms of Ramorum blight. Shoot necrosis and dieback are typical of Ramorum shoot dieback and are seen on rhododendron, blueberry and on conifers like Grand fir and Douglas fir. Some plants like California bay laurel and camellias shed the infected leaves and may decline slowly, but a large number of spores is produced on the leaves and the spores can be transferred to oak and tanoak trees and cause sudden oak death.
A list of host plants and plants associated with Phytophthora ramorum is available on the USDA-APHIS-PPQ website (http://www.aphis.usda.gov/ppq/ispm/pramorum/pdf files/usdaprlist.pdf), this list is updated regularly and on the September 11, 2006 update, 105 plants were listed as being hosts (47) or associated with P. ramorum (56). Compare this to the list published on September 14, 2005, when the total number of hosts and plants associated with P. ramorum was 85, there were 40 plants listed as hosts and 45 associated plants, within one year, 20 plants have been added to the host list due to increased efforts in monitoring and research. Proven hosts are regulated in whole or in part and plants associated with P. ramorum and regulated as nursery stock.
Phytophthora ramorum is believed to spread by the movement of infected plant materials (such as infected nursery stock and plants collected in infested areas), infested soils, mulch, water, rain splash and it also may be spread by air currents when it is foggy. The introduction of this pathogen could impact Appalachian forest ecosystems, native rhododendron and mountain laurel are susceptible to P. ramorum as are several oak species. The favorable climate with mild temperatures and periods of fog is also a factor that may influence the establishment of P. ramorum in the state.
During 2006 the USDA APHIS National Nursery Survey for P. ramorum was carried out and 46 states reported survey results. Alaska, Iowa, Missouri and Puerto Rico did not participate in the survey. A total of 95,295 samples were collected from 3,513 nurseries inspected across the country. From this total, 352 samples were confirmed positive in 56 nurseries in 11 states. The number of sites where positive samples were collected are: 26 in California; 13 in Oregon; eight in Washington; two in Florida; one in Alabama; one in Connecticut; one in Georgia; one in Indiana; one in Maine; one in Mississippi and one in Pennsylvania. In 2005 national nursery surveys were performed in 48 states and 96 nurseries in seven states were found to have plants that tested positive for P. ramorum, whereas in 2004 infected plants were found in nurseries in 22 states.
Kentucky participated in the National Nursery Survey in 2006 and approximately 14,936 plants were inspected for Ramorum blight in 46 nurseries and retail outlets in 20 counties. Of these 687 showed symptoms indicative of infection by an organism in the genus Phytophthora and 192 composite samples were collected. Of the 46 nurseries surveyed, 20 nurseries were trace forward nurseries. Samples were collected from 35 nurseries in 19 counties: Bath (1), Boone (3), Breathitt (1), Bullitt (2), Campbell (1), Clark (1), Fayette (1), Franklin (2), Gallatin (1), Hancock (1), Jefferson (9), Jessamine (1), Kenton (1), Laurel (4), Madison (1), Nelson (2), Pulaski (1), Russell (1) and Scott (2). No samples were collected from eleven trace forward nurseries, because the plants had already been sold.
There are approximately 50 species in the genus Phytophthora and samples are tested using an ELISA assay that identifies Phytophthora species. Samples that test positive in ELISA are tested by USDA-APHIS using the Polymerase Chain Reaction assay (PCR) using specific primers for P. ramorum. During the survey 42 samples tested positive in ELISA for the genus Phytophthora at the University of Kentucky; DNA was extracted from these samples and was sent to the USDA-APHIS-PPQ for testing by PCR. All 42 samples tested negative for Phytophthora ramorum by PCR and Phytophthora ramorum has not been detected in nursery surveys in Kentucky in 2006.
Nursery Surveys have been performed in Kentucky in 2003, 2004, 2005 and 2006, through collaboration between the Departments of Plant Pathology and Entomology and the Office of the State Entomologist at the University of Kentucky, and the USDA - APHIS. During these surveys Phytophthora ramorum was not found in Kentucky.
Globalization of the nursery trade allows for offshore production of ornamentals that can be commercialized directly to the consumer, and for introduction of new and exotic plants that can be used by plant breeders and growers to develop novelty varieties for increasingly demanding consumers. Plants and plant products are transported long distance across country and state borders to bring these new and interesting plants to the market. Although there may be many benefits to the introduction of new plants, the long distance movement of plants and plant parts across state and national borders has associated with it the risk of introducing diseases and pests to areas where they were not previously present. The introduction of new diseases and pests may lead to environmental issues and management problems that can be complicated and expensive to deal with. It is always important to obtain healthy plants from reliable sources and to keep in mind that further precautions and surveys may be necessary to exclude pathogens and pests that may be introduced into the state.
On recent agronomic samples in the PDDL we have seen Pythium root rot on alfalfa and Diplodia ear rot on corn.
On ornamental and turf samples, we have diagnosed Volutella canker on boxwood; Pestalotia leaf spot on magnolia; black root rot on holly; rust on bluegrass and dollar spot on bentgrass.
NOTE: Trade names are used to simplify the information presented in this newsletter. No endorsement by the Cooperative Extension Service is intended, nor is criticism implied of similar products that are not named.
Lee Townsend
Extension Entomologist