jul-aug-2020

IN YOUR ORCHARD Dust Management Wherever possible, take steps to minimize harvest dust. Reducing dust is a safety consideration on public and private roads as well as an environmental contaminant. Make sure your employees know that you are concerned with dust and show them how to operate equipment to reduce dust generation, especially near roads and property edges. Adjust sweeper head heights to 0.5-inches off the ground wherever possible so that the equipment isn’t digging into the orchard floor and moving that dirt into the windrows. Slow harvester speed near field edges to reduce dust and point blower spouts into the orchard when sweeping near roads and neighbors. Pest Management Navel Orangeworm Timely harvest is a very effective way to reduce NOW damage, especially when pressure from this pest is high. Once on the orchard floor, the nuts are very difficult for the female moths to find. Timely harvest ahead of the big flights – third and fourth generations – helps reduce damage. Keeping track of NOW flights in different blocks, based on info from egg traps or female moth traps, is critical to knowing generation timing. Also, field sampling of NOW damage in Nonpareil nuts before pickup can give growers and PCAs a sense of how much pressure the pollinizer varieties face. Assuming that a one percent hull split spray went out in late June/early July and a second within 14 days of the first, growers and their PCAs must decide if an additional spray is needed as July comes to an end and the third generation of NOW is about to arrive. The added expense of spraying pollinizers may pay off under high NOW pressure. To slow pesticide resistance development in NOW to the very few effective insecticides available for control of that pest, do not apply the same pesticide chemistry to two consecutive NOW generations. For example, if Altacor ® was used on the second generation of NOW, do not treat the third generation with Besiege ® or Minecto ® Pro, both of which contain the same or similar chemistry as Altacor ® (IRAC group 28). Check with your PCA regarding materials, PHI and efficacy (PHI is measured from shake date, not pickup). Check almonds as they go into stockpiles for NOW damage. Fumigate stockpiles as needed, as the pest can continue to feed and reproduce within stockpiles. Mites Late mite flareups can cause partial defoliation at harvest, slowing nut drying and potentially reducing flower development (and crop) for next year. There are effective miticides in the market, so the key to avoiding mite damage is to track populations as they build so sprays can go out on time. Monitor mites as July progresses into August. Use of the UC IPM mite sampling protocol can help make the expensive decision of whether to include a miticide with a later NOW spray ahead of harvest. Spray Coverage Late season insecticide and miticide sprays require good coverage to deliver effective pest control. Slow sprayer speeds (two miles per hour) deliver the best possible spray penetration into the canopy. Higher spray volumes (150 to 200 gallons per acre) have been shown to deliver better NOW control. Ants Timely shake (when 100 percent of the nuts are at stage 2C or drier) reduces exposure to NOW after shaking but means a longer drying time on the orchard floor. That means longer exposure to protein feeding ants (pavement and southern fire ants) and significant risk of ant damage (see photo) if the ants are not controlled. Most growers use 3 6 A L M O N D F A C T S