California Avocado Commission: The National Weather Service (NWS) has issued an alert concerning high wind gusts and well-above normal heat for the Los Angeles and Oxnard regions.
NWS notes that moderate to strong Northwest to North winds (15 – 30 mph with gusts of 30 – 50 mph) may occur through Friday, with the strongest winds (gusts as high as 65 mph) expected on Wednesday night and Thursday. The strongest and most widespread winds are predicted for the I-5 Corridor, Montecito Hills and Gaviota Pass, with winds likely to push into the San Fernando Valley and LA Basin. The wind prone areas of Santa Barbara County, Antelope Valley and Santa Clarita Valley also are expected to have gusty conditions.
These windy conditions could lead to downed trees and branches, possible power outages, damage to portable temporary shelters, and hazardous driving conditions due to cross winds and dust. Fire weather concerns are rated “minimal” due to high fuel moistures.
Beginning Friday, through next Monday or Tuesday, NWS also is predicting extended “very warm” conditions with max temperatures of 85˚F – 95˚F. The hottest days are expected to be Friday and Saturday, with temperatures 15 – 20 degrees above normal. Low temperatures will range from 55˚F – 65˚F and minimum humidities will vary from 12 – 25 percent.
To ensure that California avocados maintain their superior quality it is imperative that growers manage their trees and harvest their fruit according to best management practices as outlined below.
Growers should be irrigating their trees now, in advance of the above normal temperatures and warm dry winds, to ensure that their trees are fully hydrated. It is recommended that an additional 50 percent of the budgeted amount of water be applied the days prior to the forecast winds and above normal temperatures. A well-watered tree will tolerate the stress of high temperatures and drying winds much better than a tree that is suffering from water stress. Signs of heat damage to trees include fruit drop, shoot damage, leaf burn and in severe cases leaf drop.
Every attempt should be made to harvest fruit when temperatures are below 90 °F, and no harvesting should take place when temperatures exceed 95 °F. Temperature in the shade should be monitored during harvesting and, when possible, harvesting crews should be moved to the coolest, least exposed areas of the grove.
Field bins should be placed under the trees while being filled to protect the harvested fruit from sunburn. Once filled, bins should be moved to a shade structure (open-sided roofed building), or covered with bin covers or light-colored tarps if they cannot be immediately transported to the packinghouse. Never leave filled bins exposed to the direct sun. The surface layer of fruit can easily heat up to more than 15 °F above ambient temperature when exposed to direct sun. Acute sunburn will only show on fruit after it is packed and is a major quality detractor.
To avoid water loss and decreased fruit quality do not hold fruit too long after harvest. Transport fruit to the packinghouse at least once per day, if not twice daily. Bins should not be left in the grove for more than 8 hours after harvest. Cover bins during transport to avoid sunburn and to reduce water loss.