Monitor for pests or their damage: Preharvest

  • Citrus flat mite
  • Mealybugs
  • Alternaria late bight
  • Botryosphaera panicle and shoot blight
  • Verticillium wilt (late strikes)
  • Other canker diseases
  • Ground squirrels
  • Jackrabbits
  • Meadow voles
  • Pocket gophers
  • Crows
  • Scrub jays
  • Yellow-billed magpies
Click on photos to enlarge. Names link to more information on identification and management.
Citrus flat mite injury to pistachio nuts and rachis.

Citrus flat mite damage

Identification tip: Citrus flat mite feeding causes dark brown lesions on green nuts and on the rachis of the cluster.

Pistachio clusters heavily contaminated with Gill's mealybug, Ferrisia gilli, honeydew, and sooty mold.

Mealybug damage

Identification tip: Mealybug feeding can lead to heavy honeydew and sooty mold contamination on clusters.

In fall, Gill's mealybugs aggregate on the trunk and main scaffolds, where they give the surface a white, bearded appearance.

Mealybug infestation

Identification tip: Mealybugs aggregate on the trunk and main scaffolds, where they give the surface a white, bearded appearance.

Symptoms on ripe fruit.

Alternaria late blight damage

Identification tip: Dark lesions develop on ripening fruit and leaves infected with Alternaria.

Alternaria leaf blight lesions on pistachio leaves.

Alternaria late blight damage

Identification tip: Dark angular or circular lesions on leaves of both male and female trees are caused by Alternaria infection.

Alternaria leaf blight lesions on the surface of a pistachio fruit.

Alternaria late blight on ripening fruit

Identification tip: On immature fruit the symptoms appear as small black lesions about 1 mm in diameter.

Blighted shoots, leaves and fruit clusters are discolored brown. Panicles are blighted when temperatures increase in late spring and summer (May - July).

Botryosphaeria panicle and shoot blight damage

Identification tip: Leaves, nuts, and stems turn brown on shoots infected with Botryosphaeria.

Large brown Botryosphaeria lesions on older pistachio leaves.

Botryosphaeria panicle and shoot blight damage

Identification tip: Large, dark brown lesions with wide yellow margins on several old leaves.

Small, black pycnidia of Botryosphaeria on a green fruit.

Botryosphaeria panicle and shoot blight damage

Identification tip: Small, black pycnidia spot the surface of an immature fruit.

Collapse of peach shoot tips caused by Verticillium wilt.

Verticillium wilt

Identification tip: Verticillium wilt becomes apparent when leaves on one or more branches, often on only one side of the tree, turn yellow or wilt.

Phytophthora canker on crown and lower trunk.

Other canker diseases

Identification tip: Excessive sap on trunk and scaffolds. Sparse, pale foliage can indicate Phytophthora. Cankers can be found in the bark at the crown area.

California ground squirrel.

Ground squirrel adult

Identification tip: The adult head and body ranges from 9 to 11 inches long and it’s somewhat bushy tail is about as long as its body. The fur is mottled dark and light brown or gray.

Adult jackrabbit.

Jackrabbit (hare) adult

Identification tip: The adult is about the size of a large house cat. It has very long ears, short front legs, and long hind legs.

Adult meadow mouse.

Meadow vole (meadow mouse) adult

Identification tip: Adult moles are larger than the house mouse but smaller than rats. Compared to deer mice, however, voles have a more robust body, less obvious ears, and a relatively shorter tail.

Adult pocket gopher, Thomomys sp.

Pocket gopher

Identification tip: The adult pocket gopher is 6 to 8 inches long with a stout brown, gray, or yellowish body and small ears and eyes. It is rarely seen aboveground.

Holes chewed in a microsprinkler drip line by California ground squirrel, Spermophilus beecheyi.

Jack rabbit (hare), Meadow vole, or Pocket gopher damage

Identification tip: Rabbits, voles, and gophers may gnaw drip irrigation lines.

The crown and lower trunk of this tree have been girdled by voles, Microtus sp.

Meadow vole damage

Identification tip: Voles feed on bark around the root crown. Small trees are most susceptible to being completely girdled.

Adult common crow.

Crow adult

Identification tip: This bird is large, chunky, and black, with a heavy bill and feet.

Adult scrub jay, Aphelocoma coerulescens.

Scrub jays

Identification tip: An aggressive bird, the scrub jay is about 12 inches long and distinguished by its crestless head, olive-gray back, and white throat that is outlined in blue; head, tail, and wings are blue.

Adult yellow-billed magpie.

Yellow-billed magpie

Identification tip: This large noisy bird has distinct black and white markings on its body and a very long tail.

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