Petal Fall

Monitor for Asian citrus psyllid by conducting visual surveys of newly forming flush, and by using sweep net surveying or tap sampling. Use an Asian citrus psyllid-effective insecticide if spraying for citrus thrips. Otherwise, manage psyllids according to the Citrus Pest Management Guidelines. In areas where Asian citrus psyllid is not known to have established (central and northern California), if Asian citrus psyllid is found, contact your local county agriculture commissioner’s office, and report it.

A CDFA liaison will provide research-backed information on Asian citrus psyllid management and coordinate treatments of commercial citrus.

Monitor fruit for immature citrus thrips (late April through June, or through October on lemon).

• Keep records (example citrus thrips monitoring form PDF).
• Examine leaves for natural enemies, especially Euseius tularensis

Manage if needed according to the Citrus Pest Management Guidelines.

Monitor trees for forktailed bush katydid (March through June). Use a time search or net shake to search for nymphs. Manage if needed according to the Citrus Pest Management Guidelines.

• Monitor California red scale males using pheromone-baited sticky traps (March through October), plus additional methods (e.g. calculate degree days, monitor crawler tapes, and examine harvested fruit).
• Keep records (example red scale monitoring form—PDF).
• Distinguish male scales from scale parasites and other important insects caught in sticky traps.
• Release Aphytis melinus if biological control is compatible with the overall management program.

Look for spider mites and other mites.

• Monitor leaves for citrus red mite.
• Keep records (example citrus red mite monitoring form—PDF).
• Look for natural enemies, especially Euseius tularensis and sixspotted thrips.

Manage if needed according to the Citrus Pest Management Guidelines.

Monitor cottony cushion scale (May) to see if the vedalia is providing biological control; it is too late to relocate vedalia. If the threshold is exceeded, manage later according to the Citrus Pest Management Guidelines.

Examine twigs for citricola scale females to alert you whether management later may be needed. Be sure to distinguish citricola scale from brown soft scale.

Look for other pests and their damage to fruit or damage to leaves and twigs, especially:

• Ants, including Southern fire ants, Argentine ants, and gray ants
• Caterpillars, including amorbia, citrus cutworm, fruittree leafroller, omnivorous leafroller, and orange tortrix
• European earwig (March through June) in mature trees or infesting wraps of young trees

Manage if needed according to the Citrus Pest Management Guidelines.

Look for brown garden snail.

• Heading into warm weather, relocation of decollates is not advised.

Manage if needed according to the Citrus Pest Management Guidelines.

Use pesticides according to their labels to avoid killing honey bees.

Look for diseases that cause symptoms on fruit, leaves and twigs, and on limbs, trunks, and roots, especially:

• Brown rot decay (if fruit is likely to be exported to China, then this disease is of concern)
• Dry rot root
• Hyphoderma canker (fruiting bodies develop in the spring)
• Phytophthora gummosis (crown and trunk) and Phytophthora root rot

Record the date and location of problem trees or sites. Manage if needed according to the Citrus Pest Management Guidelines.

Survey weeds. Manage vegetation if needed according to the Citrus Pest Management Guidelines.

Look for vertebrates, especially ground squirrels, pocket gophers, rabbits, and roof rats. Manage if needed according to the Citrus Pest Management Guidelines.

Provide proper cultural care and good growing conditions to improve tree health and fruit yield, including:

• Fertilize if needed.
• Irrigate and adjust scheduling to meet trees' varying water needs.
• Prune if needed, such as removing dead twigs and branches to reduce bacterial blast (citrus blast) inoculum.

Survey weeds. Manage vegetation if needed according to the Pest Management Guidelines.

Look for vertebrates, especially ground squirrels, pocket gophers, rabbits, and roof rats. Manage if needed according to the Pest Management Guidelines.

Provide proper cultural care and good growing conditions to improve tree health and fruit yield, including:

• Fertilize if needed.
• Irrigate and adjust scheduling to meet trees' varying water needs.
• Prune if needed, such as removing dead twigs and branches to reduce bacterial blast (citrus blast) inoculum.

Determine whether application of plant growth regulator is warranted. Consider

• Gibberellic acid (GA3) for fruit set of clementine mandarins.
• 2,4-D to increase fruit size of navels, Valencias, and grapefruit.
• Naphthalene Acetic Acid (NAA) to thin fruit and indirectly increase fruit size of oranges, tangerines (mandarins), tangelos and tangors.

Harvest mature fruit in coordination with other management activities to ensure good postharvest fruit quality and food safety.

• Educate and supervise workers regarding fruit-handling Best Management Practices (BMPs).
• Inspect fruit quality before bins are moved from the picking site to identify grove areas where management practices need improvement.