All Hands on Deck!
By Robert Smith, Agronomist
Hurricane Hilary, downgraded to a tropical storm, rolled through parts of California's San Joaquin Valley this weekend (thru Monday), bringing rare August downpours and high winds that may have a significant effect on the region's crops.

Grapes, almonds, pistachios, tomatoes and other local crops are particularly vulnerable as we enter and push through the harvest window. The economic impact on growers will be significant.  

The storm hit the Central Valley traveling up the Highway 99 corridor and the east side of the Valley the hardest. Rainfall amounts ranged from 0.0 to 2.00 inches depending on your location, along with heavy winds. Most growers are scrambling and applying fungicides to pistachios, tomatoes, and grapes.
Ultra Gro Products can fit in and help
This is a good time for the addition of foliar nutrients as needed. Consider adding UG 2-17-17, Quick-K, or UG Control, along with minors, to your foliar rides.

Why UG Control?
While Phosphite does not have any activity on Alternaria, Phosphite can be used as a biostimulator that improves plant performance by activating molecular, biochemical and physiological responses, especially when applied in the presence of sufficient Phosphate. Control also has an MKP component to it, that can help fight mold.

Black Mold in Tomatoes (Alternaria alternata
Black mold is a disease of ripe tomato fruit that appears in the field after rain. Disease incidence is higher with increased late-season rain. Fungal spores need 3 to 5 hours of wetness to germinate. After germination they can infect fruit by directly penetrating the epidermis. A crop can be heavily damaged within 4 to 5 days following a period of rain and high humidity. The fungus also readily colonizes any wounds on the fruit, including sunburned areas.

Late season fruit rots: Sour rot complex, Botrytis and Ripe rot are major concerns. Though it is usually dry across the grape growing regions of the SJV, this untimely rain can lead to disaster. Once berries split due to rain, yeasts and bacteria quickly invade damaged fruit, leading to rots that attract fruit flies. Before you know it, you have a stinking mess on your hands, aka; Sour Rot Complex. What makes this disease complex so dangerous for growers is that once it is spotted in vineyards, it’s already a problem. Do your best to get ahead of it.

Alternaria Late Blight of Pistachios (Alternaria alternata)
Alternaria late blight occurs as black angular or circular lesions on leaves of both male and female trees. When pistachio fruit is maturing, the lesions appear with a red halo on hulls, according to the IPM website. Black spores develop in the center of the leaf lesions when humid conditions prevail in orchards. Leaf infections can cause severe premature defoliation. Excessive growth of the fungus invades the fruit kernels deterioration of hulls, resulting in kernel decay, which, in turn results in shell staining, “You cannot wait and watch for this disease,” Michailides said. “If you are in an area where it develops historically year after year, you have to spray. If you see symptoms, it is too late.” 

Alternaria Leaf Spot of Almonds (Alternaria alternata)
Late rains will increase the risk of Alternaria. This pathogen requires warm temperatures and leaf wetness to infect almond trees. Small circular lesions form, eventually increasing to the diameter of 1/2-3/4.” Occasionally, there is a yellow halo. Older lesions often develop a black ring of spores. The disease develops rapidly under favorable conditions. The varieties ‘Carmel,’ ‘Sonora,’ ‘Monterey,’ ‘Winters,’ and ‘Butte’ are more susceptible than other varieties. If Alternaria is left uncontrolled, the resulting defoliation of trees can lead to immediate yield loss in the current year and compounded productivity losses in the years that follow.

Final Takeaway: Get ahead of it!
Give your Crop Advisor a call to learn more.