June 1, 2015

This report covers conditions and observations made between Monday, May 4 and Sunday, May 31, 2015. The next report is scheduled for Monday, June 29, 2015. 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 southern region present the fully solidified nuts of the Sonora variety in the Chowchilla area of Madera County, followed by a sprayer controlling the weed growth and workers adjusting the tie-downs in new plantings in the Earlimart area of Tulare County.

Growers in the southern San Joaquin Valley experienced variable conditions during May, with cloudy skies bringing rain to the region on several days. Daily high temperatures increased gradually during the period, varying predominately between the lower 70’s and lower 80’s for much of the month. However, readings increased during the last week of the month, reaching into the mid 90’s in all areas of the region. Morning low readings exhibited much more stability, with readings reported between the upper 40’s and upper 50’s. As previously noted, rain fell throughout the region as clouds rolled in from weather systems east of the state, dropping a total of a few hundredths of an inch to as much as 0.75 inch over several days.

The mild conditions of the past few weeks provided orchards in the southern San Joaquin with a bit of a respite, reducing water consumption and allowing growers to delay or shorten irrigations. While saving a bit of water in the process, water remains a focal point for all growers in the region. Observers are reporting that growers were largely able to meet their orchard’s water requirements during the month. However, visual impacts are becoming more apparent, with yellowing from poor quality water and excessive stress in instances of insufficient water becoming more visible in all areas of the region.

While monitoring moisture levels, growers have also been scrutinizing insect populations. Observers are reporting that Navel Orange Worm pheromone traps, used to monitor the life cycle development of this serious pest have been catching significant numbers of male moths. University advisors have also noted the potential for serious damage this year, resulting from poor “mummy” shaking conditions during the winter, leaving an excessive number of over-wintering larvae in the orchards. All in the region are expecting the hull split to begin at an earlier than normal date this year, due to the elevated temperatures experience in the weeks following the completion of the bloom. As a result, growers are especially vigilant this year, hoping to time any required treatments as accurately as possible with the proper stage of crop and insect development in order to minimize damage to the crop.

Growers have initiated treatments for web-spinning mites, using preventative materials targeted at damaging species, as well as applications to prevent summer foliar diseases. The rain events experienced during the period have increased the potential of Scab and Rust, which can cause significant defoliation if unchecked. Treatments for these fungal diseases must be completed prior to infection in order to be effective.

Over the coming weeks, growers will be working to prepare their orchards for the upcoming harvest. As can be expected, moisture management will play a critical role in order to bring the crop to maturity, as growers balance limited water supplies against the needs of the crop.

Current weather at the National Weather Service
Erine Reichmuth
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