Aquatic Weed Control meeting set
We are offering an Aquatic Weed Control meeting for those irrigating nursery stock out of reservoirs, ponds, etc. Aquatic weeds present a challenge. They can cause delays in irrigation schedules.
There has already been an algae bloom reported in West Tennessee this year. It is time to plan your defense. Topics will include correct reservoir construction to reduce weeds, using alternative methods of weed control as well as preventing weeds with chemicals. The meeting will be March 17, at 7 p.m. at the TSU Nursery Research Center on Cadillac Lane. The emphasis of this program will be geared to controlling weeds in water that will be applied over ornamental crops. Creig Kimbro will be the instructor.
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It is expected that stress from last year’s freeze and drought will cause a high population of Asian ambrosia beetles (AAB) this spring. We can not detect a stressed plant as well as the AAB.
The name Asian ambrosia beetle has been changed to granulated ambrosia beetle by the Entomological Society of America’s Common Names Committee.
This will only cause further confusion because this insect will now be known by two names. You may see granulated ambrosia beetle with Asian ambrosia beetle after it in parenthesis.
The annual trigger for ambrosia beetle activity is generally three consecutive warm, sunny days in the 70’s or so. Ambrosia beetles have been trapped in Warren County as early as February during mild winters but typically not before late March with peak flights occurring in April. (March 23 in McMinnville in 2007) They begin boring the same day they are found in traps. Contact Mark for trap plans and more details at (931) 473-8484 or by e-mail at [email protected]
The peak flight period may vary by several weeks among different years. Ambrosia beetles overwinter as adults, so a flush of flight activity can occur as soon as the weather becomes suitable.
Producers should scout heavily for the toothpicks of frass sticking out from the trunks, until after the plants break dormancy to provide early detection.
They bore straight into the trunk to make brood galleries (cleaned out tunnels to lay their eggs and in which to grow the ambrosial fungi on which they feed). The tree should be sprayed at the first signs of frass tubes poking out of the 1 mm entry holes in the bark.
If the trees are sprayed early enough, the beetles will either back out of the holes to try to get away or die going in.
Some people will apply bark sprays to specific high value plants or to all of their plants when the first granulated ambrosia beetles are caught in the traps. Others scout and only spray if the first signs of attacks are found.
I do not know which approach is best because most nurseries are not attacked by this pest on a given year. Usually only one or a few types of plants are attacked at a given location but the plant types that they do attack can sustain considerable mortality.
We recommend permethrin Perm-UP 3.2 EC for the commercial nursery, Astro for the landscape (same ingredient). Chlorpyrifos at the higher AAB rate can also be used.
We suspect 3 to 4 hours of good drying time will be required prior to a rain. It should be repeated at 10 to 14 day intervals. Stop when plants break dormancy.
More details, photos and trap plans can be found online at http://www.uaex.edu/Other_Areas/publications/PDF/FSA-7064.pdf