Almond Crop Progress Report 02.07.24

The transition from spring to summer brought a significant rise in temperatures throughout the Central Valley, with readings consistently surpassing 100°F for several days. Interestingly, this period also saw a surge of monsoonal moisture, leading to thunderstorms in various parts of the Valley and resulting in heavy showers and occasional hail, particularly in Fresno County. Daily maximum temperatures soared dramatically at the beginning of the period, climbing from the mid-80s to just 100 degrees for several days, then fluctuating between the lower 90s and as high as 107°F. The highest temperatures recorded in the central and southern San Joaquin Valley.

In June, orchard activities centred on supporting the developing crop and preparing for the upcoming harvest. As in the previous month, pest management and irrigation were the primary tasks during this period.

The rise in temperatures increased the orchards' water consumption, prompting growers to either increase their irrigation frequency or volume. Those reliant on irrigation districts with a rotation schedule, where water is received on a set timetable, had limited options to prevent stress on their trees. Conversely, growers with access to on-demand water had more flexibility. However, everyone is concerned about forecasts predicting temperatures of 110°F or higher in the coming weeks.

Growers dealing with excessive weed growth intensified their efforts to manage the vegetation, aiming to ensure a clean orchard floor before the harvest begins. Those who provided minimal care to their orchards, resulting in a heavy vegetative load, face significant problems. Vegetation left on the orchard floor at harvest presents two main challenges that can negatively impact yields by reducing harvest efficiency:

• Increased difficulty in moving the crop from beneath the trees into windrows
• There is a higher likelihood of ejecting a portion of the crop along with the vegetation as it passes through the harvester.

Several other issues were also addressed during this period:

• Observers reported incidences of Scab and Rust, fungal diseases that can defoliate trees if left untreated. Treatments to control these "summertime" fungal diseases must be applied before infection occurs.
• Increasing populations of web-spinning mites, Leaf-Footed Plant Bugs and Stink Bugs, which can cause Brown Spot in the harvested crop, have been noted.
• Growers have started applying bait materials targeting problematic ant species. These materials must be carried into the colony by the ants to sterilise the queen, eliminating egg production and reducing the infestation to below-damaging levels.

As June ends, growers and their Pest Control Advisors shift their focus to the beginning of the hull split in early harvesting varieties. Observers have reported the first signs of hull split in blank nuts (those where the hull and shell formed without a kernel) around mid-month. These blanks typically split about 10 days ahead of the "sound" nuts, indicating the start of hull split season and the need for treatments to control Navel Orange Worm. Observers noted that the earliest treatments began in the final days of June, with initial applications targeting other edges of orchards and older, weaker plantings that tend to split earlier. Most growers and PCAs plan to begin treatments in the coming week as the split starts in each orchard.

Growers are particularly concerned about Navel Orange Worm damage this year, given the significant losses experienced in the 2023 crop. Nearby abandoned orchards and those receiving minimal care due to tight cash flows have exacerbated the problem, serving as reservoirs for NOW due to the presence of uncontrolled mummy nuts harbouring NOW larvae. As adult moths emerge from these mummies, they can fly for miles to infest neighbouring orchards. Many growers have employed mating disruption techniques, releasing pheromones within the orchards to confuse male NOW moths and reduce successful mating. However, treatments at hull split are ultimately the final opportunity to reduce infestations and crop loss before the harvest.

via Blue Diamond Growers