Northern California - July 1, 2013
This report covers conditions and observations made between Monday, June 3 and Sunday June 30, 2013. The next report is scheduled for Monday, August 5, 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 northern region show the splitting hulls of the Nonpareil and an example of the heavily laden Monterey in the Williams area of Colusa County, followed by a down-the-row shot of the Nonpareil in the Durham area of Butte County.
An unusually wide range of conditions were reported during the month in the Sacramento Valley; from record setting heat to a winter-like storm that delivered a modicum of rain. Maximum temperatures spiked quickly during the first days of the period, rising from the upper 70’s and lower 80’s to as high as 108 degrees by Saturday, the 8th. Readings then slipped back into the upper 70’s and lowers 80’s for the majority of the period before tumbling into the upper 60’s as a winter-like storm system passed over the northern half of the state on the 23rd and 25th of the month. Observers noted that the unusual storm system dropped from a few hundredths to as much as 0.5 inches of rain around the Sacramento Valley. Stable conditions followed the storm’s exit, allowing maximum readings to approach the 110 degree mark as a heat wave enveloped the state during the period’s closing days. Morning minimum temperatures followed a similar pattern, dipping only into the upper 70’s on the hottest days, while receding into the low to mid 50’s during the balance of the period. Winds continued to play a role in the region’s weather during June with quite a few days recording winds in excess of 10 mph.
Observers are reporting that the rainfall during the period increased the potential for foliar fungal diseases, particularly Alternia. Accordingly, some growers with particularly susceptible plantings have treated to prevent infection. However, with the beginning of the hull split, grower’s attention has turned toward the various pre-harvest tasks. First among the items to be completed is treatment for Navel Orange Worm, NOW, in orchards planted to susceptible varieties. Many will make split applications in an effort to sufficiently cover the flight of the adult moths and ensure that adequate protection coincides with egg laying by the females on the splitting hulls. Those with building populations of damaging ant species have also begun treatments with targeted bait formulations.
The beginning of the hull split also heralds a period of more intense water management by those wanting to decrease the incidence of fungal hull rot infections. Given the heat wave currently baking the region, growers must work a delicate balance of withholding water to 50% of the tree’s consumptive use in order to reduce moisture levels within the splitting hulls, while not subjecting the crop to undue stress. University research shows that a mild stress for approximately two weeks at the initiation of hull split can greatly reduce the incidence of infection. Growers have been working to stretch their water supplies all season long and will return to their normal irrigation pattern after a two week period.
As shown in the third of this report’s photos, the degree of weed growth in the orchards follows the pattern of irrigation, with low volume systems having weeds only in the areas that the water can reach. In any case, vegetation on the orchard floor must be managed prior to shaking in order to ensure efficient nut removal during the harvest. Observers are reporting that shaking of the first orchards to be harvested should begin during the first days of August.
Current weather at the National Weather Service
Photos: Dennis Meinberg and Ryan Christy, 7/1/13
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