Courtesy County Integrated Pest Management Committee
PESTS AND DISEASES
LEAST TOXIC TREATMENT
HARD PESTICIDE TREATMENT
|Knapweed||Best time to mow is when plants are in full flower before first seeds form.|
|Western Cherry Fruit Fly
Adult flies have clear wings with black stripes, 1/2" in size. Eggs are laid under skin of fruit at about the time thet start to turn pink. Small maggots, or worms, and feed on cherry flesh.
|Trap adults with red ball or yellow sticky traps. Treat adults with Pyrethrin if >2 flies per trap each week in red ball or yellow sticky traps.||Spray with malathion if >2 flies per trap per
week. Allow a minimum of three days before harvesting cherries!
Once cherries are ripe, it's usually too late to spray.
Various species of tiny red and white greenish-white spiders (0.06"in length), cause yellowing and browning of plant leaves. They produce webbing when populations are very high.
|Keep plants well irrigated. Decrease nitrogen
Spray with Incecticidal Soap. Repeat applications may be necessary as mites reproduce quickly. Add 1T/gal of sulfur to Insecticidal Soap if population isn't decreasing. (This can burn leaves of sensitive plants, especially if appliaed on a hot and sunny day.)
|Usually not necessary inless populations are high.
For commercial applications, use one of the organosulfur compounds
such as Omite (Propargite). Spray tops and undersides if needles or
leaves are browning due to high mite population.
Aviod using carbaryl (Sevin) which kills predators and causes mite outbreaks.
|Black Vine Weevil||Apply parasitic nemotodes or Beavaria bassiana (Naturalis-O) to soil around base of plants affected and water in immediately. keep soil moist.||none necessary|
|Pine-Needle Scale||Treat tiny, orange crawler stage only.
Crawlers hatch from underneath the white scales on last year's pine needles. Treat with Insecticidal Soap or oil spray if >5-10 needles scale per shoot.
Excessive nitrogen and water stress increases scae problems.