nov-dec-2020

ANNUAL GROWERS MEETING percent average insect damage. Research has shown that if mummy shaking is required near bloom, you can shake into bud swell without a significant loss of yield. However, shaking most be completed prior to the start of bloom. Other NOW control measures include mating disruption, timely harvest, and hull split treatments. Spring spray may be useful if the neighbors don’t have high populations flying. “But if that is the case, spend the spring spray money on an additional hull split spray,” said Niederholzer. For best results, he suggests rotating chemistry classes when spraying for NOW in order to minimize chemical resistance. Change materials with each generation of NOW. For example, if making a mummy spray with Proclaim, consider Altacor ® for the June/July generation, and Intrepid ® for the third generation in August. Each of those products is based on a different chemistry. Scale and Spider Mites Scale can sneak up on you, Niederholzer warned. “They are not strong fliers, but they can build up over time. And if predatory wasps are not present, scale can multiply quickly and kill lower branches and reduce yield. A dormant spur sample can reveal whether healthy scale is present. If they are, treat with oil and an insect growth regulator, such as Sieze or Centaur, for example. Oil can suppress low to moderate scale populations. Four gallons of oil with Bravo used for scab will also suppress scale, he said. Spider mites can be controlled with beneficial insects and mites, while the use of miticides can harm beneficials. It is advised to wait for the economic threshold to be reached before applying miticides. Then spray carefully. Niederholzer cautions that unsprayed plant tissue is unprotected tissue. Peach twig borer (PTB) continues to be a major pest in almonds. There are no economic thresholds for PTB but there are numerous effective control options, says Niederholzer. Dormant season offers good opportunity for excellent coverage; delayed dormant spray offers the same good opportunity. In both cases extra caution should be taken to avoid drift or runoff. Bloom is the time to use B.t which offers very good control of PTB depending on the number of times it is sprayed. Other materials can be toxic to bees, so caution is advised. PTB are strong fliers so early sprays don’t eliminate them but help manage the pest. Ants were a major cause of rejects in many orchards in 2020. Ant bait can be very effective, but it must be used when it is fresh or the oil becomes rancid and the bait is much less effective. Wet bait is also less attractive. Good weed management is essential because some weeds are more attractive food sources to ants than baits. Spraying for leaffooted plant bugs is tough on an IPM program. Treatment starts in March or April with a material that controls the leaffooted bug, but is disruptive to mite and scale control programs. For more information on IPM for almonds visit the website http://ipm.ucanr.edu/ . Mummies Per Tree Mummies Per Acre Eggs/a Spring Eggs/a in June/July Eggs/a in August with hull split spray Eggs/a in August (no hull split spray) 2 250 465 2,168 23,000 92,000 5 620 2,900 13,550 144,00 576,000 These totals set a grower up for severe reject levels. 2 2 A L M O N D F A C T S