Central California - June 3, 2013
This report covers conditions and observations made between Monday, April 29 and Sunday, June 2, 2013. The next report is scheduled for Monday, July 1, 2013. However, in the event of any significant occurrences prior to that date, this site will be updated as soon as possible.
This report’s photos for the central region present examples of the Leaf-Footed Plant Bug. First, a shot of a mating pair on the Fritz variety, followed by two recently hatched nymphs along with their eggs and finally, a shot of a Lacewing larvae feeding on a group of eggs. Please refer to the photos found in the southern region report for an example of the damage this insect pest can produce.
Breezy conditions dominated the central region’s weather during May, holding temperatures below seasonal normal levels for much of the period. Variable conditions allowed daily maximums to reach their peak values several times during the month, first as the period began and again at mid-month when readings reached into the upper 80’s and lower 90’s and finally in the period’s closing days when readings approached the 100 degree mark. In between, temperatures dropped into the lower 70’s in all areas of the region, nearly 15 degrees below normal values for the period as cut-off low pressure systems swept over the state. While forecasters had called for the possibility of scattered showers, precipitation was scarce with wettest locations reporting only a few hundredths of an inch. Morning lows exhibited a bit more stability than the daily maximums, with most mornings producing minimum values between the upper 40’s to upper 50’s, while warmest mornings dipped only into the lower 60’s.
Winds continued to play a role in the region’s weather, with wind speeds reaching above 10 mph on the majority of days and above 20 mph on quite a few as well. While growers reported some blown over trees and broken branches, greatest impact from the winds was produced by the drying effects of the winds, which held water consumption at elevated levels in spite of the lower temperatures.
Observers have reported that the first solid kernels in the Nonpareil variety were noted at mid-month along the west side of the region approximately 10 days ahead of last year. This is a direct result of the warm temperatures experienced during the weeks following the completion of the bloom. Lower temperatures experienced during May failed to significantly impact the pace of development and observers have noted that kernels in all varieties are now fully solidified.
Grower’s activities during the period were focused primarily on irrigation, fertility and pest management. Many have explored new protocols for nitrogen management developed by the University of California and have been adapting their applications accordingly. However, most attention was given to management of insect pests as a result of increased pressure from Leaf-Footed Plant Bugs, LFPB, which made their appearance in many orchards. As can be seen in the photos accompanying this report, this is a rather large insect that has the ability to pierce though the hull and shell, literally killing the kernel and causing the nut to abort if damaged prior to solidification. The insect can also damage the kernels after solidification, increasing reject levels by causing gumming and a discoloration of the kernel at the feeding site known as Brown Spot. Growers with Fritz, Aldrich, Sonora, Monterey and Price were particularly vigilant given the insect’s preference for these varieties and their ability to cause significant crop losses. While growers were reluctant to employ a disruptive insecticide that could also impact beneficial insect populations, the rapid spread of this aggressive pest forced many to treat their orchards to eliminate the infestations. Given that most growers were also beginning treatments with preventative miticides targeted at damaging mite species, growers were able to add materials required to control the Plant Bugs to the application, saving an additional pass through the orchards.
A few growers with Fritz also reported symptoms of Bacterial Spot, which causes the symptoms similar to Leaf-Footed Plant Bug, a clear “gumming” of sap dripping from the hull as well as foliar damage.
As is normally the case for the period, irrigation was prime activity. Growers have been closely monitoring their orchard’s moistures needs, balancing requirements against the supply of water available. These efforts will continue into the fall. Growers will also be monitoring Navel Orange Worm traps as they work to effectively and efficiently time treatments to control this traditional insect pest prior to harvest. Those with excessive mummy nuts remaining in the trees from last year’s crop will be particularly vigilant.
Current weather at the National Weather Service
Photos: Mel Machado, 6/3/13
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