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(originally published January/February 2017)

Navel orangeworm (NOW) populations exploded in 2017, costing growers tens of millions of dollars in reduced quality and lost yields. In a year where double-digit damage estimates from nut processors were not uncommon, the question heading into the coming growing season (and future seasons beyond 2018)—how do we limit damage from this pest? Is our current arsenal of integrated pest management (IPM) tactics enough to keep damage in the desired 1 to 2 percent range given the two million (plus) acres of commercial nut crop habitat in California (not to mention the myriad other crop and non-crop plants that play host to NOW)? This article covers the “tried-and-true” strategies, as well as where we need to head in the future of NOW management to ensure clean, safe, and profitable nut crops for years to come.

A four-pronged approach to NOW management in nut crops has been suggested for years based on University research and field success stories. These include: sanitation, minimizing damage by other sources, timely (early) harvest to avoid late generation flights, and insecticide treatments as deemed necessary by monitoring pest activity and crop phenology.

anthr Red Aleppo 8 Aug 24

(originally published November/December 2017)


Anthracnose of pistachio: In July 2016, putative diseased samples were collected from two pistachio (Pistacia vera) orchards in northern California (Glenn County) with black and sunken lesions on leaves and rachises. Samples were of the Red Aleppo, Joley, and Kerman cultivars. Eventually, individual fruit were totally blighted.  . These fruit blight symptoms looked different from the Botryosphaeria (Bot) panicle and shoot blight and did not bear any characteristic pycnidia of Botryosphaeriaceae fungi. Instead some of the fruit lesions developed slimy, pink ooze by harvest time. Lesions on the leaves were black and angular and also some developed the same slimy, pink ooze on the surface

Figure 6 Actual SWP Measurement

(originally published September/October 2017)

Among the most basic observations that can be used to manage irrigation in orchard crops are visual cues of crop water stress. However, these cues can be somewhat subjective and are often expressed after plant stress is higher than desired. Measuring midday stem water potential (SWP) using a pressure chamber is a quantitative method for evaluating plant water status, and relationships have been established between pressure chamber measurements and tree growth and productivity. From these relationships, guidelines have been developed to assist growers in making irrigation scheduling decisions. 

Fotografie aeriana photo number 1

(originally published July/August 2017)

One of the most discussed precision ag technologies in the last 4 years has been Unmanned Aerial Systems (UAS), not only because it is a “cool” technology, but also because there is confusion in its use or misuse.  Can I fly these without a license and if I’m not getting paid?  What do I do with all of this imagery?  Do we already have too much data?  This article will outline some examples of how West Hills College uses UAS in permanent nut and row crops while educating our students about UAS as tools for the grower.