Franz Niederholzer3 CommentsDecember 21, 2012Horticulture, Insects, Weeds

What did I learn at the Almond Board’s annual conference?

The Almond Board of California’s annual conference is a chance to connect with others in the almond industry, listen to world class researchers talk about their work, and check out a huge almond-focused trade show all at one event. The 2012 meeting was last week (Dec 11-13).  Here is a quick review of some of the things I picked up from researchers and informed industry members at that meeting…

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David Doll0 commentsDecember 11, 2012General, Insects

On-line Learning Resource Available for UC IPM Year Round IPM Programs

Written by Peter Goodell, UC IPM Specialist, Kearney Ag Center The UC Statewide IPM Program has announced the availability of an on-line tutorial to aid in the use of Year Round IPM Programs. Year Round IPM Programs were developed as another means to retrieve information from the comprehensive Pest Management Guidelines. While the Guidelines are organized by pest, the Year Round Program condenses a year’s worth of management activities for key pests into one checklist arranged by season or crop stage. Over half the crop groups in the Guidelines have a Year Round program associated with it,almond being one.

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David Doll3 CommentsNovember 30, 2012Insects

The Importance of Winter Sanitation

2012 was a bad year for navel orangeworm (NOW). This was due to a lot of factors, which include:  Mild winter temperatures in 2011/2012, leaving a high overwintering population of NOW; Dryer in-season conditions in 2011 that made it harder to shake the nuts from the trees; Lack of winter rains reduced the ease of removing mummies; Poorly timed hull-split sprays; and a slightly above average temperatures through the growing season,  increasing degree days, which reduced times between NOW generations, increasing populations.

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Franz Niederholzer0 commentsAugust 17, 2012Insects

Hull split spray(s) for pollinators

Nonpareil harvest has been going for more than a week in the south Sacramento Valley. The third generation of navel orange worm (NOW) eggs are beginning to appear on egg traps in the region. As the Nonpareil nuts hit the ground, NOW female moths will find other places such as pollinator variety nuts to lay their eggs. So, pollinator nuts, especially in varieties like Monterey, can be damaged by NOW once hull split begins in that variety. In areas with high NOW populations, it may be worth considering spraying one or more pollinator varieties when hull split begins to reduce worm damage (click here to see an earlier post on hull split spray timing).        Spray timing for pollinators depends many factors including timing of NOW egg laying, Nonpariel harvest timing, and material choice. The county ag commissioner’s office tells me that, for purposes of determining spray timing based on PHI, harvest begins when the crop leaves the tree and ends – for that variety — when that crop leaves the orchard. If a pollinator variety is showing hull split before the Nonpareil are shaken, NOW are laying eggs, and the decision to protect the pollinator nuts is made, a spray should go on before the Nonpareil nuts are harvested – at the legal PHI – to give the best possible worm damage reduction. Previous spray history (Were the Nonpareils sprayed? When was that? What was the material?) will influence the spray timing as well.   Almond growers have a variety of pesticides available to reduce NOW damage and those materials have a wide range in PHI (see table below). Short PHI pesticides generally have shorter residual in the field, but those materials may have a fit in NOW management in pollinators, especially when working around Nonpareil harvest. Short residual

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David Doll4 CommentsJuly 15, 2012Insects

Timing of Hull-Split Spray – IGRs v/s Pyrethroids

There have been a few questions about the timing of hull-split sprays with the various products available. Our suggested timing for the spray depends on the product planned to be used. Insect growth regulators (IGR) (i.e. Intrepid, Success, Altacor, Belt, etc) should be applied at the onset of hull-split – just as the suture becomes defined and the nut pops open when force is applied. This is about the same time that the blanks begin to split in the tops of the trees on the outside rows. This timing is in contrast to the application of pyrethroids. These products (i.e. Asana, Pounce, Warrior, etc.) should be applied later than an IGR, around 2-5% hull split. The timing difference is due to the differences in activity and persistence of the products. IGRs tend to be more effective in controlling eggs, neonatal and developing larvae, while pyrethroids do a better job in knocking down adults moth populations. The activity of the IGRs also tends to persist longer in the field. Since the IGR has longer persistence and tends to target the developing larvae, it has to be present on the almond surface before the egg hatches/larvae continues to develop. Since these sprays are going out earlier than in the past, bracket sprays may be needed within areas with high NOW pressure. This is an important consideration if dealing with later harvesting varieties which will be exposed to the later flights of NOW.

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Franz Niederholzer1 CommentJune 12, 2012Insects

Getting the Best Spray Coverage from a Hull Split Spray

Franz Niederholzer, UC Farm Advisor, Colusa/Sutter/Yuba Counties   Hull split is not far off. Where needed, an effective hull split spray can be the difference between good and bad (costly) reject numbers. Spray timing and pesticide selection are important parts of a good worm (and mite) control at hull split, but so is spray coverage. A bad spray job can waste time and money. In recent research conducted by Dr. Ken Giles (UC Davis Dept of Ag and Biol Engineering) and funded by the Almond Board of CA, hull split spray coverage and navel orange worm control was less in the tops of mature almond trees compared with that in the lower canopy. Here are a few things to consider when setting up your sprayer(s) for hull split spraying that should help improve spray coverage in the tree tops. Airblast sprayers are air carrier sprayers. The pesticide droplets go where the air from the sprayer’s fan goes. Increasing the spray volume per acre will not change coverage in the parts of the canopy – usually the tops – where sprayer air doesn’t reach. How can a grower make sure that good spray coverage is being obtained throughout the tree? Usually this means driving slow, giving the air from the sprayer fan time to reach the tree tops. How slow? Slow enough to give good coverage in the tops of the trees. In 2011, Dr. Giles and his team found that 2.0 MPH compared to 2.5 MPH sprayer speed significantly improved navel orange worm control at hull split. Slower was better. Not sure what speed to drive in your orchard(s) with your sprayer(s) for the best spray coverage? Check ground speed and spray coverage in the orchard just before hull split. Here are some examples of how to do this: Watch the

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David Doll0 commentsMay 4, 2012Insects

Considerations For Managing Ants In Almonds

Walter J. Bentley, Regional IPM Entomologist UC Kearney Agricultural Research and Extension Center Ant damage to almonds continues to be a difficult problem for farmers to manage.  In all areas of the state populations of the three species of ants which cause damage appear to be increasing.  From Fresno County going south to Kern County the California fire ant (also called the southern fire ant), Solenopsis xyloni, is the damaging species.  Another, less common species, is the thief ant, Solenopsis molesta, which is slightly smaller than Xyloni.  In Merced, Stanislaus, and San Joaquin Counties both the California fire ant and the pavement ant Tetramorium caespitum  can be found causing damage.  In the Sacramento Valley the pavement ant is the predominant species.  Although almond farmers will know, from past history of damage, whether or not they have a problem species in the orchard, there are other species that are considered more beneficial than harmful.  These include the bicolored pyramid ant, Doriomyrma bicolorand the native gray ant, Formica aerata.  This latter species has been found to actively feed on peach twig borer in unsprayed peach orchards.  The best way to separate the damaging species from those not causing damage is by examining the thin waist between the last pair of legs and the abdomen (stomach).  Both the pavement and the California fire ant possess two bumps or nodes while the beneficial species have only one node.  Also, the damaging species will often be found with weeds growing within the nest and are easily excited by disturbing the soil near their nests.  Finally, the pavement, California fire ant, and thief ant will aggressively bite and sting.  The California fire ant sting, in particular, is quite painful. While control information has applied to all three damaging species, monitoring methods and thresholds where only developed

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David Doll2 CommentsDecember 11, 2011Diseases, Insects

Dormant Spray Considerations for Almonds

Scab lesions on green wood of almond. Being one of the quieter times of the year, the dormant period is a prime time to assess orchard issues and begin applying strategies to reduce various diseases and insect pests. Surveying the orchard and sampling new growth and spurs can help identify problems of scab, San Jose Scale, Navel Orange Worm, and mites. If populations are high enough, dormant strategies can be applied to reduce the damage to the upcoming season’s crop. Scab. If a scab outbreak and the corresponding mid- to late-season defoliation were experienced this past year, a dormant/delayed dormant application of copper and oil should be considered. This spray is effective in reducing and delaying sporulation of scab twig lesions, thus reducing in-season disease incidence. It should be used in combination with properly timed bloom and petal fall sprays. Based on field observations, orchards with significant scab outbreaks in 2010 that followed the above recommendations had obvious suppression of the disease in 2011, and were able to keep the leaves on the trees until late November. Red Halos caused by San Jose Scale feeding/infestation in almond. Insect Pests. Spur samples should be selected throughout the orchard to determine the presence of San Jose Scale (SJS), European Red Mite (ERM), and Brown Almond Mite (BAM). Spurs should be pulled from a main scaffold with 100 spurs samples from the orchard. If 20% of the spurs selected are infested with scale, then a one-time oil application at 6-8 gallons per acre should be applied. If over 60% of the spurs are infested, the oil application should include an insect growth regulator that targets SJS. It is important to control SJS as high populations can kill spur wood, reducing crop load. Obvious signs of scale infestation include a red halo found on

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David Doll2 CommentsOctober 28, 2011Insects

Late Season Varieties and NOW Infestation

I am getting several reports from consultants, growers, and processors of high percentages of Navel Orange Worm (NOW) damage on the late harvested almond varieties. These reports have varied, but in all cases, damage has exceeded the targeted rejection rate of 2%. This has caught many people off guard. So, why did this occur? The cooler spring weather experienced meant a delayed hullsplit and harvest. This delay was most pronounced within Monterey and Fritz, which were about two to three weeks behind the “normal” harvesting time.  Harvest was delayed further by the early-October rain event. This increased “hang time” of the almonds within the tree provided the opportunity for more NOW damage. These varieties were exposed to the 2nd flight (during hullsplit), the 3rd flight (during harvest and drying), and 4th flight (during drying) of NOW which led to a greater rate of infestation. Since most growers applied a single NOW spray timed at 5% of Nonpareil hullsplit, these varieties were not only exposed to high populations of NOW, but were left without any type of chemical protection. A second NOW spray timed for the hullsplit of the Monterey and Fritz would have provided effective NOW control.  Egg trap monitoring would have indicated the need to spray at this time. Keep in mind that NOW develops more quickly on new crop than on mummies. It is also important to note that almonds are still susceptible to NOW infestation even after shaking. Increased time on the ground from poor drying conditions have also played a part in increasing the levels of infestation. Shook almonds were also exposed to the 3rd flight of NOW as well as a partially emerged 4th flight, and may partly explain the high number of young larvae within the hulls and kernels. Earlier this year, Walt Bentley, UC

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