Almond set mixed despite heavy bloom

California’s 2010 almond bloom was spectacular, but nut set is mixed, according to Agronomist/PCA Eli Akel, Akel AG Consulting at Clovis, who consults with growers in Fresno, Kings, Madera and Tulare counties.

“In some Monterey and Fritz blocks you couldn’t even see bark on the limbs because of all the blooms,” he says. “The showy bloom had some Nonpareil producers expecting a lot more from their trees, but the resulting nut set didn’t measure up.

“Growers whose orchards were hit with the freeze last in 2009 are happy — their trees had higher bloom density and higher nut set.

Fritz and Monterey bloomed earlier than Nonpareil, he says, and overall, the bloom cycle was short. Pollinators opened Feb. 14, culminating in a full bloom across soft shell varieties Feb. 22.

“So far, the trend is the reverse of last year, when Fritz didn’t have a good crop, the Monterey crop was average and the Nonpareil had a decent crop,” Akel says

In some cases this spring, hard shell variety growers saw a wide variation in the bloom pattern. In one block he checked, Buttes were at 90 percent bloom while only half of the Padres were at or near full bloom. On the same day in a different block, Butte bloom was 100 percent compared to just 30 percent Padre.

Aldrich, Padre and Nonpareil varieties did not set well. Nonpareils had a higher nut set with pollinators such as Avalon, Monterey and Wood colony, but a lower set if the third pollinator was Aldrich.

“That kind of variation between varieties, which results in poor overlap and poor pollination, can occur with a short bloom cycle,” Akel says. “Poor pollination can also occur during a short bloom, if you don’t have enough bees. For example, some growers who stocked 2.5 hives per acre this year probably would have benefitted by having 3.5 hives.

“For short bloom cycles, bee hive count and hive strength are imperative for high yield. Some growers say their young trees exhibited a higher set than older, larger trees, because bees had a smaller volume of trees to deal with.

“Colony strength was a key factor this season. Blocks where colonies averaged above 12 frames have a record crop, while growers with colonies that were split into less than an eight frame average prior to being moved into the orchard had a fair nut set.”

The wet spring produced more disease pressure. If a grower didn’t apply at least two bloom sprays, brown rot was a problem, he says.

An almond grower himself, Akel expects that the fallout from wet, cold conditions this spring will result in different kinds of challenges than growers have faced in a while. Sporadic rains combined with hot weather, for example, could alter insect flights and affect the type and timing of control practices. Also, this year’s wet spring produced an abundance of weeds.

TAGS: Tree Nuts
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