Backyard Orchard News
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San Jose scale is a small, slow moving insect that can cause significant, long term economic damage to prune orchards. The orchard in the picture below was removed shortly after the picture was taken due to extensive scaffold damage and loss of bearing wood caused by a buildup of San Jose scale.
Scale populations build slowly over time, so an annual scale “checkup”– and treatment when necessary -- can avoid this kind of damage. Especially if you have been following an “aphid only” dormant spray program of a pyrethroid (Asana®, Warior®, etc.) only or pyrethroid plus less than 2 gallon of oil/acre, a program that will not control scale, check your orchard for scale this winter.
Dormant spur sampling – done by the grower or PCA – is the annual scale checkup. The timing for this key part of an overall prune orchard management program is now through January.
Details on how to take a dormant spur sample and how much scale is enough to recommend a spray treatment are found by calling your local University of California Cooperative Extension office or on the internet at: http://ipm.ucdavis.edu/PMG/r606900511.html.
If San Jose scale shows up in the dormant spur sample, the best time for a control spray is before bloom. A high oil rate (4-6 gallons/acre) applied in the dormant (good) or delayed dormant (best) timing is enough to control low to moderate San Jose scale populations. The oil smothers the pest. The higher the oil rate, the better the control. If the San Jose scale population is high in an orchard (more than 20% of spurs checked show live scale) then oil plus a pesticide labeled for San Jose scale (Seize WP, Centaur, diazinon, etc.) will be needed. Consult with a PCA when deciding what pesticide(s) to use.
A dormant spray with a high rate of oil has the added benefit of advancing prune bloom several days. How many days? That depends on the year and is impossible to predict.
Finally, the higher the spray volume per acre, the better the scale control. If you have a real problem and want to get the best control, use 400 gallons per acre (gpa) of spray volume and spray in the delayed dormant period. Spraying in the dormant period with 100 gpa gives good control, but not great control.
Don’t let scale sneak up on you. Schedule your scale checkup now.
UC subtropical horticulture specialist Mary Lu Arpaia, who is based at the Kearney Agricultural Research and Extension Center, was one of four UC specialists who traveled to Sarajevo Oct. 24-28 at the request of local officials to present a condensed version of the UC Postharvest Technology Short Course. Nearly 100 participants from 11 countries attended the program, which included lectures and a field tour. Simultaneous translation was offered in Bosnian and Russian.
“To me it was a very interesting experience,” Arpaia said. “The participants were very engaged in the course and asked lots of questions that were spot-on in terms of sharing practical information. They were very keen to get information on the ‘how to’ and solving practical situations."
Mary Reed of the UC Postharvest Technology Center said interest in the short course was remarkable given that the first estimate from planners was for 25 participants.
“Interest just kept growing and growing as word got around,” Reed said. “Given the challenges of traveling in the region, acquiring visas, and obtaining agency permissions, the participants really had to overcome significant obstacles in order to attend.”
Arpaia said the four-days she spent with Eastern European farmers in an area that suffered bitter ethnic conflicts in the 1990s also made a profound personal impression.
“I had been aware of the war in the Balkans but never fully appreciated the impact of that war on people’s lives,” she said. “You can still see the physical scars of the war – mortar shell scars on buildings, burned and abandoned buildings – and, more dramatically, hear the angst of the people when they talked about those times. It is another example to reflect upon in terms of how lucky we are in the U.S. and that we need to forever be vigilant not to allow animosities to fester due to ethnicity, religion etc.”