Mite management in tree fruits under hot and dry weather conditions

John Wise, Michigan State University Extension, Department of Entomology - June 13, 2023

Updated from an original article written by John Wise, Rufus Isaacs and Larry Gut.

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

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
Onager Optek	Pome, stone, grape	TSSM	Egg/larvae	Mid (or threshold)**	6-8 weeks
Apollo	Pome, cherry, peach	ERM	Egg/larvae	Early***	8-12 weeks
Apollo	Pome, cherry, peach	TSSM	Egg/larvae	Mid (or threshold)	6-8 weeks
Agri-Mek, ABBA	Pome, stone, grape	ERM, RM	Motiles*	Early****	8-12 weeks
Agri-Mek, ABBA	Pome, stone, strawberry, grape	TSSM	Motiles*	Mid (or threshold)	6-8 weeks
Minecto Pro	Pome, stone	ERM, RM	Motiles*	Early****	8-12 weeks
Minecto Pro	Pome, stone	TSSM	Motiles*	Mid (or threshold)	6-8 weeks
ABBA	Pome, plum, grape, strawberry	ERM, RM	Motiles*	Early****	8-12 weeks
ABBA	Pome, plum, grape, strawberry	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
Gladiator	Pome, stone, grape	TSSM	Motiles*	Mid (or threshold)	6-8 weeks
Zeal	Pome, stone fruits	ERM	Egg/larvae	Early (or threshold)**	8-10 weeks
Zeal	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
Envidor	Stone fruits	TSSM	Egg, motiles*	Mid (or threshold)	6-8 weeks
Nexter	Pome, stone¹, grape	ERM, RM	Motiles*	Mid (or threshold)**	6-8 weeks
Nexter	Pome, stone¹, grape	TSSM	Motiles*	Mid (or threshold)**	6-8 weeks
Portal	Pome	ERM, RM	Motiles*	Mid (or threshold)**	6-8 weeks
Portal	Pome	TSSM	Motiles*	Mid (or threshold)	6-8 weeks
Nealta	Pome, grape, stone fruits	ERM	Motiles*	Mid (or threshold)**	6-8 weeks
Nealta	Pome, grape, stone fruits	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
Kanemite	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
Acramite, Banter	Pome, peach, plum, grape, strawberry	TSSM	Motiles*	Mid (or threshold)	6-8 weeks
Danitol	Apple, grape	ERM	Motiles*	Mid (or threshold)**	4-6 weeks
Danitol	Apple, grape, strawberry	TSSM	Motiles*	Mid (or threshold)	4-6 weeks
Brigade	Pear	ERM	Motiles*	Mid (or threshold)**	4-6 weeks
Brigade	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
Vendex	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.
²Including pear blister mite.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).