Navel orangeworm (NOW) pressure has been high the last few years and possible wet El Nino weather could be good and challenging for winter sanitation.
Cooperative Extension Integrated Pest Management Advisor Emily Symmes says wet weather can help winter sanitation in nut crops but those rains could make orchard accessibility tough.
More About NOW Management
Two cultural practices—effective removal and destruction of mummy nuts in fall or winter and rapid, early harvest—provide the most effective control of navel orangeworm. Insecticide treatments are needed when these practices are not carried out properly, when infested alternate host trees (fig, pomegranate, or pistachio) are nearby, or to achieve very low levels of damage. When infested trees of these alternate hosts are harvested, navel orangeworm moths may migrate into almond orchards. Treating border rows (at least 10 rows) may be adequate to prevent the moths from infesting the almond crop when navel orangeworm densities are low to moderate in a given area. Sprays are timed using egg traps, monitoring of hullsplit, or degree-days. Two parasitic wasps may be found in orchards, but they cannot be relied on to provide effective control alone without other cultural or compatible chemical practices also being used. Read more about navel orangeworm from the UC IPM website.