Mite management in tree fruits under hot and dry weather conditions

There are many options available for mite control in fruit crops.

Mite feeding injury on peach leaves
Mite feeding injury on peach leaves. Photo by Mark Longstroth, MSU Extension.

Weather conditions in the last month have resembled the arid climate of Western U.S. more than a normal Michigan spring. Given these conditions, it is logical to expect higher populations of orchard pests that thrive in hot and dry climates.

In typical years, the European red mite (ERM) tends to be the dominant mite pest of Michigan tree fruits, especially in apples. This season, growers should be on the lookout for twospotted spider mites (TSSM) and rust mites (RM) such as the plum nursery mite.

The twospotted spider mite overwinters in ground cover and moves up into trees as ground vegetation dries. Twospotted spider mite adults are similar in size compared to European red mite, but have two distinct spots located on the front half of their body behind the eyes. Eggs are white (whereas European red mite eggs are red), and motile stages typically construct webbing on the underside of leaves. For summer populations, examine leaves from several locations in the orchard using 50% spur leaves and 50% shoot leaves. Treat based on the following thresholds:

  • 2-3 mites/leaf from mid-May to mid-June
  • 5-7 mites/leaf from mid-June through July
  • 10-15 mites/leaf in August

Presence of predaceous mites (more than one per leaf) may justify delaying a treatment and repeating the cycle the following week.

High populations of plum nursery mite can cause “firing” in tart cherries. Firing looks similar to fire blight in apple where a branch or multiple branches on a tree appear dead and all or majority of the leaves on that branch are completely brown and dried up. Branches will die as a result of this firing. Plum nursery mites are extremely small and live on the upper and lower leaf surfaces and feed primarily on new growth. Use a high powered hand lens (30x) and look for the tiny, wormlike mites with two pairs of legs along the leaf midribs. If mites are observed, particularly in trees with firing, a miticide may be needed to protect the overwintering health of cherry trees as it is at risk from mite injury.

There are many miticides available for control of pest mites, but not all products are active on all three species, so care should be taken to select the best product. The following table is designed to summarize several key variables that can help you determine which miticides are optimal for your program.

Compound

Fruit crop

Mites

Life stage target

Seasonal timing

Residual control

Superior, Stylet Oils

All fruit crops

ERM, RM

egg/larvae

Early (pre-bloom)

2-6 weeks

Lime-Sulfur

pome, stone,blueberry

RM3

motiles*

Early (delayed-dormant)

2-6 weeks

Dimilin

Pear

RM

Motiles*

Early (pre-bloom)

2-6 weeks

Onager Optek

Pome and stone fruits

ERM

Egg/larvae

Early***

8-12 weeks

Pome, stone, grape

TSSM

Egg/larvae

Mid (or threshold)**

6-8 weeks

Apollo

Pome, cherry, peach

ERM

Egg/larvae

Early***

8-12 weeks

TSSM

Egg/larvae

Mid (or threshold)

6-8 weeks

Agri-Mek, ABBA

Pome, stone, grape

ERM, RM

Motiles*

Early****

8-12 weeks

Pome, stone, strawberry, grape

TSSM

Motiles*

Mid (or threshold)

6-8 weeks

Minecto Pro

Pome, stone

ERM, RM

Motiles*

Early****

8-12 weeks

Pome, stone

TSSM

Motiles*

Mid (or threshold)

6-8 weeks

ABBA

Pome, plum, grape, strawberry

ERM, RM

Motiles*

Early****

8-12 weeks

TSSM

Motiles*

Mid (or threshold)

6-8 weeks

Agri-Flex

Pome, grape

ERM, RM

Motiles*

Early****

8-12 weeks

Gladiator

Pome, stone, grape

ERM, RM

Motiles*

Early****

8-12 weeks

TSSM

Motiles*

Mid (or threshold)

6-8 weeks

Zeal

Pome, stone fruits

ERM

Egg/larvae

Early (or threshold)**

8-10 weeks

Pome, stone, strawberry, grape

TSSM

Egg/larvae

Mid (or threshold)**

6-8 weeks

Envidor

Pome, plum, grape

ERM

Egg, motiles*

Early (or threshold)**

8-10 weeks

Stone fruits

TSSM

Egg, motiles*

Mid (or threshold)

6-8 weeks

Nexter

Pome, stone1, grape

ERM, RM

Motiles*

Mid (or threshold)**

6-8 weeks

TSSM

Motiles*

Mid (or threshold)**

6-8 weeks

Portal

Pome

ERM, RM

Motiles*

Mid (or threshold)**

6-8 weeks

TSSM

Motiles*

Mid (or threshold)

6-8 weeks

Nealta

Pome, grape, stone fruits

ERM

Motiles*

Mid (or threshold)**

6-8 weeks

TSSM

Motiles*

Mid (or threshold)

6-8 weeks

Magister

Pome and stone fruits, blueberry, caneberry, grapes

TSSM, ERM, RM

Eggs, Motiles*

Mid (or threshold)

4-6 weeks

Kanemite

Pome fruits

ERM

Motiles*

Mid (or threshold)**

6-8 weeks

Pome, strawberry, blueberry, stone fruits

TSSM

Motiles*

Mid (or threshold)

6-8 weeks

Acramite, Banter

Pome, peach, plum

ERM

Motiles*

Mid (or threshold)**

6-8 weeks

Pome, peach, plum, grape, strawberry

TSSM

Motiles*

Mid (or threshold)

6-8 weeks

Danitol

Apple, grape

ERM

Motiles*

Mid (or threshold)**

4-6 weeks

Apple, grape, strawberry

TSSM

Motiles*

Mid (or threshold)

4-6 weeks

Brigade

Pear

ERM

Motiles*

Mid (or threshold)**

4-6 weeks

Pear, grape, strawberry, caneberry

TSSM

Motiles*

Mid (or threshold)

4-6 weeks

Hero

Blueberry, caneberry, strawberry

TSSM

Motiles*

Mid (or threshold)**

4-6 weeks

Oberon

Strawberry

TSSM

Eggs, motiles*

Mid (or threshold)

4-6 weeks

Vendex

Pome, stone

ERM

Motiles*

Mid (or threshold)**

4-6 weeks

Pome, stone, grape, caneberry, strawberry

TSSM

Motiles*

Mid (or threshold)

4-6 weeks

Spear-T

Pome, blueberry, stone fruits

ERM, TSSM

Motiles*

Mid (or threshold)**

2-6 weeks

Sil-Matrix

Fruit crops

ERM, RM, TSSM

Motiles*

Early or Mid (with multiple applications)

2-6 weeks

Venerate

Stone fruits, grape

TSSM

Motiles*

Early or Mid (or threshold)**

2-6 weeks

Sulforix

Pear, blueberry

RM2

Motiles*

Late (post-harvest)

2-6 weeks

* Motile forms include mite larvae, nymph and adult stages.
** Optimally used petal fall through August when mites reach threshold.
*** Optimally used pre-bloom through first cover.
**** Optimally used petal fall through second cover.
1 300-day PHI (preharvest interval) for cherry.
2 Including pear blister mite.

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