Pistachio > Year-Round IPM Program > Budbreak through Bloom

Pistachio

Why is budbreak through bloom important in an IPM program?

Budbreak.

Beginning to bloom.

Early bloom.

Mid-bloom.

Flower cluster at full bloom

Budbreak/bloom extends from budbreak to petal fall. Activities for this season generally occur mid-March to mid-April, but dates vary according to region, variety, and weather. Some of the key pistachio pests invade the orchard or are present in the trees during bloom, and therefore, this is a time to:

• At budbreak, identify trees with mealybugs if not done after the last harvest for future monitoring and management during late spring or early summer.
• Mow ground cover before bloom to reduce the incidence of frost, plant bug, and false chinch bug damage.
• Monitor for small plant bugs, leaffooted plant bugs, and stink bugs.
• Hang navel orangeworm egg traps.
• Look for obliquebanded leafroller strikes and leaf tying.
• Determine if fungicide treatments are needed for Botrytis blossom and shoot blight and Botryosphaeria panicle and shoot blight. ("Panicle" refers to the flower or fruit cluster.) Some treatments are started at either early bloom (5-10%) or at full bloom.

Use the photos and descriptions to familiarize yourself with the various bloom stages. Visually scan the orchard to estimate.

10% bloom

At 10% bloom, approximately 1 out of every 10 blossom buds is open. To check for this stage, look at a series of tree branches throughout your orchard. At 10% bloom an average of 1 blossom is open for every 9 closed ones on a branch.

Full bloom

Full bloom refers to the point at which the majority of flowers in the orchard are fully open; some will be past full bloom while others will be at earlier stages. The proportion of flowers that are fully open when the orchard is at full bloom can vary substantially depending on winter chilling. During high-chilling years, as many as 80% of the blossoms may reach full bloom at the same time. In low-chilling years the proportion may be below 50%.