August 31, 2015

This report covers conditions and observations made between Monday, August 3 and Sunday, August 30, 2015. The next report is scheduled for Monday, October 5, 2015. However, in the event of any significant occurrences prior to that date, this site will be updated as soon as possible.

Taken in San Joaquin County, this report’s photos for the central region show a sweeper moving the crop from beneath the trees, a windrow of the Nonpareil waiting to be removed from the orchard and a shot of an orchard in the San Joaquin Delta where the saline water drawn from the San Joaquin River has started to burn the leaves on the Monterey variety. Note that the adjoining Nonpareil variety is not showing adverse symptoms. Our feature image shows the hull spit of the Aldrich variety near Ripon.

Warm, dry conditions dominated the weather in the northern San Joaquin Valley during August, providing ample opportunities for growers harvesting the 2015 crop. Daytime high temperatures were reported at their lowest values early in the period, with temperatures rising from the mid and upper 80’s during the first week of the month. Temperatures then took on a cyclic pattern, peaking at mid-month at just over 100 degrees, then cooling into the upper 80’s before rising back above the century mark in the final week the period. Morning minimum temperatures exhibited a greater degree of stability, varying between the mid 50’s to mid 60’s throughout the period.

Harvest operations are progressing rapidly in the northern San Joaquin Valley, benefitting from the warm, dry conditions that dominated the weather over the past month. A significant number of growers have completed the harvest of the Nonpareil variety and have begun shaking their various pollenizer varieties.  Some growers are reporting difficulties with uneven maturity within the trees. This has produced situations where nuts at the ends of the branches are too dry, while those deeper within the canopy are too green, producing difficult shaking conditions, leaving nuts remaining in the trees after shaking.  Even as some growers battle with the uneven maturity of the Nonpareil, the advanced nature of the pollenizers in many plantings has spurred growers to begin shaking their second varieties without pausing to irrigate.  As this report was being prepared, many Carmel, California type varieties, Butte, Padre and even a few Monterey plantings have already been shaken.

Growers throughout the region are reporting Nonpareil yields below expected levels. Weights of truckloads coming from the fields are running lower than normal, as are the yield levels of finished kernels produced from each truckload. Greatest impacts are observed in the southern areas of the region, although growers in all areas have reported reduced production levels.

Quality levels have also been impacted this year, primarily due to infestations of Navel Orange Worm,  NOW, and to a lesser degree damage caused by ants. As has been reported all year long, growers and Pest Control Advisors have been monitoring elevated trap counts of NOW in the region’s orchards. Poor mummy shaking conditions resulting from the dry winter weather has produced higher than normal populations of adult NOW moths in the orchards. Unfortunately, a large number of growers are now reporting excessive reject losses as a result of the feeding of NOW larvae on the Nonpareil and are concerned that the life cycle timing of the insect may put their other varieties at risk, as well.

While growers in the central region generally have more water available for irrigation than those in the southern San Joaquin, orchards under water stress can still be easily found in many areas of the region. As growers withhold water from their orchards during the harvest, plantings with the lowest amount of moisture deep in the root profile are the first to show signs of stress; wilting and defoliating in the most extreme cases.

Current weather at the National Weather Service
Jereme Fromm and Mel Machado
Click an image to enlarge it.