Central 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.
The first of this report’s photos for the central region shows the splitting nuts of the Nonpareil in the Hickman area of eastern Stanislaus County, while our second image provides an example the disease Bacterial Spot, which has been observed in numerous Fritz plantings in region. Our final photo shows the degree of crop loss caused by this bacterial disease.
The central region experienced a wide range of temperatures during June, with intense heat during the opening and closing days of the period and mild, unseasonably cool readings during the middle of the month.
Daily maximum temperatures reached as high as 108 degrees on June 8th, then dropped sharply into the mid 70’s to upper 80’s for much of the period. Following the passage of a weakening winter-like storm system between the 23rd and 25th of the month, which brought from a trace to as much as .2 inch of rain and dropped temperatures into the upper 60’s, readings quickly recovered, reaching to as high as 105 degrees as a well forecast heat wave enveloped the San Joaquin Valley in the closing days of the period. Morning lows ranged from the lower 50’s to the lower 60’s for the majority of the month. However, minimums dropped only into the lower 70’s during the hottest days of the period. As has been the case since the completion of the bloom, winds continued to blow through June, with many days recording speed of 10 to 15 mph.
As may be seen in the first of the photos accompanying this report, the hull split of the Nonpareil has begun in the central region. Observers noted that blank nuts could be found splitting at mid-month along the I-5 corridor, with sound nuts splitting shortly thereafter. Hull split of sound Nonpareil nuts may now be observed along the Highway 99 corridor and in the eastern foothills, as well.
With the initiation of the hull split, growers are shifting their attention towards Navel Orange Worm, NOW, management and the upcoming harvest. Growers have begun hull split treatments to control NOW in orchards requiring control. They are also monitoring populations of web-spinning mites and hoping that early treatments with preventative materials targeted at damaging species will hold in the face of the heat wave baking the region as the period concluded.
While observers have noted that there are few problems caused by web spinning mites so far this year, some growers in the region have suffered from the affects of Bacterial Spot. This bacterial infection was first spotted in the California in Colusa County in 2006 and has been reported to have caused significant losses to the Fritz variety in Australia in past years. The most serious infections have been observed in San Joaquin County, with Stanislaus and Northern Merced also reporting infections. So far, the disease has focused on the Fritz variety. However, observers have noted that the Nonpareil is also beginning to show signs of the disease in the most severely impacted plantings.
As may be seen in the second photo accompanying this report, symptoms include a heavy, amber colored gumming at the infection site. Some have confused the gumming with that caused by the feeding of the Leaf-Footed Plant Bug noted in last month’s report. However, the gumming caused by plant bug feeding is clear. Caused by a bacterial infection, Bacterial Spot is not susceptible to the disease-controlling fungicide materials growers normally employ. As may be seen in the last of this report’s photos, the disease is capable of causing significant crop losses and growers with infected plantings are very concerned.
With the initiation of the hull split, growers will withhold irrigation to one-half of consumptive use for a two week period in an effort to reduce susceptibility to hull rot fungal infections. Given the heat wave impacting the region as this report is being prepared, growers will be working a delicate balance between wanting to reduce the amount of moisture within the splitting hull while not inducing an excessive amount of stress that can adversely impact the weight and quality of the crop. Obviously, growers will be monitoring their orchards closely as the hull split progresses.
In anticipation of the approaching harvest, growers will also soon begin final preparations to the orchard floor, mowing weeds and applying bait treatments targeted at damaging ant species. We anticipate that shaking of the first orchards along the west side of the region will begin prior to the end of July.
Current weather at the National Weather Service
Photos: Mel Machado, 7/1/13
Click an image to enlarge it