Identification and Control of Orchard Ants

David DollFarm AdvisorMerced CountyYolo/Solano County

Almond Day

Ant Anatomy

Ants Found Within the Orchard

• Argentine Ant (Linepithema humile)

• Native Gray Ant (Formica species)

• Pyramid Ant (Doymymex insanus)

• Bicolored Pyramid Ant (Doymymex bicolor)

• Small Honey Ant (Prenolepis impairs)

• California Harvester Ant (Pogonomyrmex californicus)

• Thief Ant (Solenopsis molesta)

Pest Ants of Almonds:•Pavement Ant (Tetramorium caespitum) •Southern Fire Ant (Solenopsis xyloni) •Red Imported Fire Ant (Solenopsis invicta)

Non-Problematic Orchard Ants:

Almond Ant Damage

Very Little Damage reported on Huller Grade Sheets!

Pest Ants of Almonds: Mounds

-Out of full sun-Weeds present at entrance-In areas of moisture

Pest Ants of Almonds: Pavement Ants

Pest Ants of Almonds: Fire Ants

Southern Fire Ant v/s Red Imported Fire AntPest Ants of Almonds: Fire Ants

Red Imported Fire Ant Nest

Non-Problematic Orchard Ants

Bi-Colored Pyramid

Red Harvester Ant

Non-Problematic Orchard Ants

Native Gray Ant

Argentine Ant

Scouting for Ants• May – Early June– Further South Scout earlier in May– “Stomp Test” or “Let them bite you test”

• Colonies located 3’ apart count as different county

• Five 1000’ square foot sections

• Cultural Controls– Delay Harvest and Pick-up Almonds as Quick as Possible– Longer on the ground = more damage

• Baits (Esteem, Clinch, and Extinguish)– Baits are brought back to the nest and affect whole colony– Apply baits before the heat of the summer – when ants are

closer to the surface– Do not use within 24 hours after an irrigation, 48 hours before

• Conventional Sprays (Lorsban)– Only kills foraging workers

Ant Damage Control

Finding the balance…- Longer in the tree, possibly

more NOW damage- Longer on the ground, possibly

more ant damage- Need to know populations present!

Any Questions?

Weekly Updates about almond production can be found at “The Almond Doctor,”

www.thealmonddoctor.com