Dark, rust-colored dieback symptoms of Botryosphaeria (Bot) canker. G. Moody
This disease is Bot canker. Bright, rust-colored branches and yellowing or browning of shoots or branches are the first observed symptoms. Closer inspection reveals the presence of sunken, girdling cankers at the base of the dead shoot or branch. Sometimes, the main trunk shows cankers that might extend for a foot or more in length. These cankers rarely girdle the trunk, but they will kill branches that may be encompassed by the canker as it grows. Read more info in the following publication including disease management.
Authors – Alfredo Martinez, UGA Plant Pathologist, Jean Williams-Woodward, UGA Plant Pathologist and Mila Pearce, Former UGA IPM Homeowner Specialist
Leyland cypress has become one of the most widely used plants in commercial and residential landscapes across Georgia as a formal hedge, screen, buffer strip, or wind barrier. The tree is best suited for fertile, well-drained soils. However, when young, the tree will grow up to 3-4 feet per year, even in poor soils. The tree will ultimately attain a majestic height of up to 40 feet.
Leyland cypress is considered relatively pest-free. However, because of its relatively shallow root system, and because they are often planted too close together and in poorly drained soils, Leyland cypress is prone to root rot and several damaging canker diseases, especially during periods of prolonged drought. Disease management is, therefore, a consideration for Leyland cypress.
This UGA Publication discusses several Leyland Cypress diseases and their management.
Postemergence herbicides may be applied to suppress bermudagrass populations and reduce competition with desirable turfgrasses. Repeat applications of selective herbicides are needed for best results but may be injurious to the desirable species. Furthermore, tolerance to herbicides may vary by turfgrass cultivar and end-users should consult with local Extension specialists for application rates and recommendations.
Bermudagrass Control in Centipedegrass
Centipedegrass is a popular low-maintenance lawn species in Georgia. Centipedegrass generally has slower growth than bermudagrass with less potential for competition during the summer. Clethodim (Envoy, others) and sethoxydim (Segment, others) are cyclohexenadione herbicides that inhibit lipid synthesis in grassy weeds. Sensitive species exhibit leaf injury with reddish discoloration before significant necrosis.
Bermudagrass is sensitive to both clethodim and sethoxydim and repeat applications may suppress populations in centipedegrass. Turf managers should schedule applications approximately every three weeks during active growth. For best results, add a nonionic surfactant at 0.25% v/v with clethodim to enhance spray retention and apply no sooner than three weeks after spring green up. Certain sethoxydim products (e.g., Segment) may have a built-in adjuvant already mixed in the formulation and the addition of a surfactant is not required. For both herbicides, turf managers should avoid mowing one week before or after treatment.
Bermudagrass Control in St. Augustinegrass
St. Augustinegrass is a major warm-season turfgrass used for lawns in southern Georgia. St. Augustinegrass has desirable heat and drought tolerance but is sensitive to many herbicides. Selective herbicides for controlling grassy weeds, such as crabgrass and goosegrass, are limited in St. Augustinegrass lawns. Bermudagrass infestations are also difficult to manage.
St. Augustinegrass has good tolerance to ethofumesate (PoaConstrictor, Prograss), which may be used in combination with atrazine to control bermudagrass. Ethofumesate is an unclassified herbicide that has postemergence activity for grassy and broadleaf weed control in nonresidential St. Augustinegrass and cool-season grasses. Ethofumesate has several toxic effects in susceptible species, such as bermudagrass, but arrested cell division appears to be the primary mechanism of selectivity.
Atrazine inhibits photosynthesis in susceptible weeds and is in the triazine herbicide family. Triazines interfere with electron transport during photosynthesis and eventually lead to cell membrane destruction and cellular leakage. Susceptible weeds initially exhibit chlorosis on leaf margins. Actively growing bermudagrass is sensitive to atrazine applications and its addition to ethofumesate treatments provides postemergence and some residual control of bermudagrass. Atrazine alone may provide some bermudagrass suppression but does not provide long-term control.
Applications of ethofumesate with atrazine should be initiated during bermudagrass spring green up. Herbicide regimens that begin on actively growing bermudagrass in summer will likely be ineffective. St. Augustinegrass often responds to applications with stunted growth and discoloration. Repeat applications should be made after 30 days or once turf has recovered from any potential injury. See the current edition of the Georgia Pest Management Handbook for rates and further information about bermudagrass control.
Bermudagrass Control in Tall Fescue and Zoysiagrass
Fenoxaprop and fluazifop are used for postemergence grassy weed control in tall fescue and zoysiagrass. Sensitive weeds exhibit injured leaf tissue with reddish discoloration while plant nodes become necrotic and die. Theses herbicides have no activity on broadleaf weeds but provide excellent grassy weed control.
Fenoxaprop (Acclaim Extra) and fluazifop (Fusilade) may be used alone in tall fescue and zoysiagrass lawns. Fenoxaprop may also be used in residential and nonresidential Kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.) and other cool-season turfgrasses. Fluazifop may be used in commercial and nonresidential turf. Generally, tall fescue has good tolerance to these herbicides. There is greater potential for injury on zoysiagrass than on tall fescue from fenoxaprop or fluazifop treatments, especially fine-textured varieties.
Triclopyr (Turflon Ester, Turflon Ester Ultra) at high rates (0.75 to 1 lb ai/acre) is injurious to bermudagrass. Tank mixtures with fluazifop or fenoxaprop have been shown to reduce tall fescue and zoysiagrass injury without compromising control. The addition of an adjuvant to tank mixtures of fluazifop with new triclopyr formulations (e.g., Turflon Ester Ultra) is unnecessary and may increase turf injury.
In Georgia, initial applications of fenoxaprop or fluazifop should be scheduled around June 1 and repeated every 20 to 30 days. Fluazifop alone should be applied with a non-ionic surfactant at 0.25% v/v of spray solution. Acclaim Extra (fenoxaprop) does not require the addition of an adjuvant. See the current edition of the Georgia Pest Management Handbook for rates and application comments for fluazifop and fenoxaprop treatments for bermudagrass control in tall fescue.
Nonselective Bermudagrass Control
Spot treatments of nonselective herbicides are the most effective method for controlling bermudagrass. Glyphosate is a nonselective herbicide that is widely used for spot treatments of perennial weeds in turfgrasses. Glyphosate is a foliar-absorbed herbicide that is systemically translocated with no preemergence activity for weed control.
Spot treatments of glyphosate should be made to bermudagrass patches and surrounding areas to control any runners that may be intermingled with desirable turfgrasses. Broadcast applications can effectively renovate or kill existing vegetation but high rates and multiple applications are required to control bermudagrass. Glyphosate should be applied to actively growing bermudagrass. Repeat treatments will be required for complete control. Cultural practices that disrupt plant growth, such as vertical mowing and aerification, should be delayed for seven days after treatment.
Glyphosate requires optimum translocation in order to control bermudagrass rhizomes and plants emerging from lateral stems. Perennial grasses generally have greater translocation of photosynthate from leaves to stems in fall than spring, which increases glyphosate movement to rhizomes. Fall glyphosate applications generally control bermudagrass more effectively than summer treatments. Numerous glyphosate products are available under a wide variety of trade names.
Answer: This study indicated that people in areas with no mosquito control program had a tenfold greater risk of WNV than those in areas where mosquitoes were controlled.
Mosquito surveillance is an important component of any mosquito control program. Where arboviral diseases occur, mosquito testing is an equally important component of an arboviral surveillance program. Arboviral encephalitis can be prevented in two major ways: personal protective measures to reduce contact with mosquitoes and public health measures to reduce the population of infected mosquitoes in the environment (mosquito control). Analysis of surveillance data provides information about the timing of arboviral transmission and the risk to the public, which can trigger county-level educational programs to help reduce risk.
West Nile Virus rates by county
A study comparing two mosquito control districts showed that the program with the most mosquito surveillance and best documented larviciding and adulticiding operations had the fewest number of WNV cases. This study indicated that people in areas with no mosquito control program had a tenfold greater risk of WNV than those in areas where mosquitoes were controlled.
Southern House Mosquito, Pest and Diseases Image Library, Bugwood.org
What are the roadblocks to arboviral surveillance in Georgia? We really do not have enough data to do good predictive calculating, particularly at the State level. Predicting where and when WNV outbreaks will occur is difficult, especially in areas with endemic transmission, which is what occurs in Georgia. Most of our sentinel data do not match up with our case data, as counties doing mosquito surveillance are not necessarily the same counties where human cases are occurring. Culex quinquefasciatus (Southern house mosquito), our primary WNV vector, are not evenly distributed, so neither is risk of human cases. However, we do not have sufficient surveillance to know where risk is occurring, and maintaining mosquito monitoring systems is costly even though it is essential according to the CDC.
Where data are available, the best predictor of risk is the Vector Index, the minimum infection rate (MIR) times the number of mosquitoes per trap night (abundance), which provides 2-4 weeks lead time in advance of human cases. Where adequate surveillance is maintained, this gives sufficient lead time to implement adult mosquito control efforts, which have demonstrated success in reducing human risk, resulting in fewer WNV cases (Carney, 2008).
Reference: Carney, R.M., Husted, S., Jean, C., Glaser, C., & Kramer, V. (2008). Efficacy of aerial spraying of mosquito adulticide in reducing incidence of West Nile Virus, California, 2005. Emerging Infectious Diseases, 14(5), 747–754.
Posted July 17, 2014 on the IPM in the South blog from the Southern Region IPM Center
The EPA unveiled a new graphic that will be available to appear on insect repellent product labels. The graphic will show consumers how many hours a product will repel mosquitoes and ticks when used as directed.
The EPA’s new graphic will do for bug repellents what SPF labeling did for sunscreens. This new graphic will help parents, hikers and the general public better protect themselves and their families from serious health threats caused by mosquitoes and ticks that carry debilitating diseases. Incidence of these diseases is on the rise. The CDC estimates that there are nearly 300,000 cases of Lyme disease in the United States each year. Effective insect repellents can protect against serious mosquito- and tick-borne diseases.
The EPA is accepting applications from manufacturers that wish to add the graphic to their repellent product labels. The public could see the graphic on products early next year.
TO ALL GEORGIA STRUCTURAL PEST CONTROL LICENSEES, INTERESTED PERSONS AND PARTIES:
The Georgia Department of Agriculture (GDA) and Georgia Structural Pest Control Commission (SPCC) announce new guidance and policy to assist the industry with compliance with the current rules of the Georgia Structural Pest Control Act. The compliance fact sheets are posted under guidance policies on the SPCC webpage.
Big cities with large expanses of concrete, asphalt, and buildings are usually warmer than the suburbs or countrysides that surround them, a phenomenon known as the urban heat island effect. Now new research from North Carolina State University shows that these urban heat islands increase the number of young produced by the gloomy scale insect — a significant tree pest — by 300 percent, which in turn leads to 200 times more adult gloomy scales on urban trees.
Seven months after the mosquito-borne virus chikungunya was recognized in the Western Hemisphere, the first locally acquired case of the disease has surfaced in the continental United States. The case was reported today in Florida in a male who had not recently traveled outside the United States. The Centers for Disease Control and Prevention is working closely with the Florida Department of Health to investigate how the patient contracted the virus; CDC will also monitor for additional locally acquired U.S. cases in the coming weeks and months.
Bait Formulations. Baits must be eaten by the target pest — typically rodents, termites, ants, cockroaches, and other miscellaneous pests (Figure 2). Baits are comprised of an active
ingredient incorporated into a palatable, if not preferred, food source. Bait products usually contain inert ingredients (e.g., preservatives, thickeners, gels, and fillers) intended to stabilize and enhance the shelf life and palatability of the bait. Logically, it is important that bait ingredients (actives and inerts) not be a deterrent to feeding.
Baits are most commonly formulated as ready-to-use liquids, gels, pastes, granules, dusts,
stations, pellets, and blocks. Depending on the product’s label, baits can be used both indoors
and outdoors, are generally target-specific, and are considered environmentally-friendly
because only small amounts of active ingredient are delivered, usually from a point source.
Because baits must be eaten, it is important to keep them away from non-target organisms.
To facilitate bait consumption:
Neither the active ingredient nor any other part of the bait should be a feeding deterrent.
The food source should be palatable (perhaps even preferred) by the target pest.
In addition, for social insect pests (especially ants) it is important that the active ingredient be slow acting. Ants and termites share food with their colony mates in a social behavior known as trophallaxis (Figure 1). Trophallaxis results in active ingredient distribution throughout social insect colonies. It is, therefore, important that the active ingredient be slow acting over a range of concentrations in order to provide sufficient time for toxicant distribution among nestmates. Fast-acting active ingredients or excessively high concentrations of the active ingredient may too quickly impair a social insect’s ability to engage in trophallaxis, thereby rendering the bait less effective.
The Urban & Structural IPM program at the University of Georgia started a webinar series this year for pest management professionals. Go to www.gabugs.uga.edu to learn more, including upcoming dates, speakers, and topics. Our series now provides CCU/CEU credit in GA, AL, FL, NC, SC, and TN.
We are announcing the doubling of credit for our series, from 1 to 2 hours. Webinars from this point forward will begin at 8:00 AM and finish at 10:00 AM, while providing 2 CEUs for attendees.
Our next webinar is August 20, 2014 from 8:00 to 10:00 AM. Dr. Brian Forschler will discuss the Biology and Management of Subterranean Termites, and Dr. Dan Suiter will talk about Demystifying Wood-eating Beetles. GA operators will receive 2 hours of WDO credit.
Should you have a question about this or any other upcoming webinar, don’t hesitate to contact me at 770-233-6114 or dsuiter@uga.edu. Alternatively, visit our website at www.gabugs.uga.edu.
Cicada killer – Jessica Lawrence, NC State Entomology Department, Bugwood.org
The cicada killer wasp is the largest wasp in Georgia. The cicada killer wasp is almost two inches long. Although intimidating in appearance, these wasps are not something we humans have to worry about. Cicadas, on the other hand, should be very afraid. Cicada killer wasp adults feed on nectar but use paralyzed cicadas to feed their young.
Female cicada killers are hard to provoke to sting. The female uses her stinger to paralyze her prey (cicadas) rather than in self defense. The female’s attention is focused on providing food for her babies, so she poses little threat to humans.
Cicada killers prefer to nest in sandy open sunlit areas. As the female digs, she kicks out soil that forms a semicircle around the burrow opening. She burrows six to ten inches into the ground, prepares a chamber, catches a cicada to fill the chamber, lays an egg on the cicada, and seals the chamber. She may do this over a dozen times in one burrow.
Cicada killer – Ronald F. Billings, Texas Forest Service, Bugwood.org
When a female finds a cicada, she paralyzes it with her stinger, straddles it, and attempts to fly with it to her burrow. Because the cicada typically weighs more than she does, these flights are usually hops, with more dragging than gliding.
The egg hatches in a few days and the larva feeds on the paralyzed cicada until nothing is left but a shell. Then the wasp larva pupates within the burrow, remaining there until the next spring.
Males cannot sting; their only defense is intimidation. They patrol the nesting area, trying to divert attention away from the female, allowing her to provision her nest with cicadas. Meanwhile the male is using threatening tactics to distract potential predators. He may even dive bomb perceived threats. Since the males do not have stingers, they are completely harmless. They must rely on bluff, bluster, and bravado to protect their families.
Because cicada egg laying can be damaging to trees and shrubs, cicada killer wasps are very beneficial, providing free biological control. However, homeowners who do not want these wasps around can modify their lawn to be unappealing. A thick healthy turf with no bare spots will exclude cicada killer wasps. If turf is thin in nesting areas, identify turf problems that make the turf weak and correct them.
Cicada killer wasps will be active for only a few weeks and will be gone by mid-August in most of Georgia. If someone is bothered by these wasps, late July and early August would be a good time to take their vacation.
For more on cicada killer wasps, see these articles:
