Mite management in tree fruits under hot and dry weather conditions
There are many options available for mite control in fruit crops.
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.