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How to Manage Pests
UC Pest Management Guidelines
Floriculture and Ornamental Nurseries
Twospotted Spider Mites
Scientific name: Tetranychus urticae
(Reviewed 3/09,
updated 6/10)
In this Guideline:
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Twospotted spider mites are web-forming mites that pierce plant
cells and remove their contents. All spider mites have two body segments and
four pairs of legs as adults. Twospotted spider mite adults, as the name suggests, have two large dark
spots on the sides of their yellowish green bodies. These mites lay round eggs
that hatch into six-legged larvae. The subsequent stages, the protonymph and deutonymph
stages, are eight-legged as are the adults. Since the entire life cycle can
take as little as 8 (77° to 95°F) to 28 (50° to 68°F) days, spider mites have
many generations per year and can rapidly increase in number.
Twospotted mites suck cell contents from leaves, initially stippling
leaves with a fine pale green mottling. As feeding continues, the stippling
increases and leaves turn yellow with bronzed or brown areas; damaged leaves
frequently fall. Undersides of leaves may have many cast skins of mites, and
the webbing on foliage is unaesthetic. Plants may
become severely stunted when large mite populations are allowed to feed and the
plants may die.
Biological Control
Many different species of predatory mites are available for control of these mites
under different conditions. Phytoseiulus
persimilis is a commercially available predator of twospotted spider mite,
and it has been used to control mite populations in greenhouses and field
situations. It can reproduce faster than its prey, yet best results have been
obtained when it is released into the crop well before the spider mite populations
have built up. For more information, see BIOLOGICAL CONTROL.
Cultural Control
Because spider mites feed on a large variety of plants, keep
production areas free of weeds, which can serve as hosts to the mites.
Carefully inspect plants being brought in to start a new crop to ensure that
they are free of mites. Rogue or treat infested plants.
Monitoring and Treatment Decisions
Monitor the crop regularly, as indirect sampling methods (such as
sticky cards) are ineffective. Observe the undersides of leaves with a 10X hand
lens, and watch for changes in plant foliage that are characteristic of mite
feeding.
Except as noted, the materials listed only kill active stages of
mites, so more than one treatment may be necessary to break the life cycle.
Follow label directions regarding reapplication times. For guidelines on when
to treat, see ESTABLISHING TREATMENT THRESHOLDS.
Selected Materials Registered for Use on Greenhouse or Nursery
Ornamentals
Read and follow the instructions on the label before using any pesticide.
Before using a pesticide for the first time or on a new crop or cultivar, treat
a few plants and check for phytotoxicity. Also consider pesticide resistance
management and environmental impact.
Class |
|
Pesticide (commercial name) |
Manufacturer |
R.E.I.1 |
Mode of action2 |
Comments |
|
botanical |
A. |
cinnamaldehyde
(Cinnacure)
|
Proguard |
4 |
— |
Use product
within 10 days of breaking seal. May cause phytotoxicity to tender tissue
growth on plants. Do not apply to stressed plants or newly transplanted material before roots are established. |
carbamate
|
A. |
methiocarb*
(Mesurol 75W)
|
Gowan |
24 |
1A |
Apply in 50 gal
water. Repeat as necessary up to 4 applications/season. Do not apply with oil or foliar fertilizer. |
carboximide |
A. |
hexythiazox
(Hexygon 50DF)
|
Gowan |
12 |
10A |
No chemigation. Ovicidal/larvicidal action. Use only 1 time per crop or once a year. |
carboxylic acid |
A. |
bifenazate
(Floramite)
|
Chemtura |
12 |
un |
Do not use in
successive applications; apply at least two alternative products between
treatments of bifenazate. Primarily effective against motile stages but has some ovicidal activity. |
macrocyclic lactone |
A. |
abamectin
(Avid 0.15EC)
|
Novartis |
12 |
6 |
Label permits low-volume application. |
oil3 |
A. |
clarified
hydrophobic extract of neem oil#
(Triact 70)
|
OHP |
4 |
un |
Do not spray
plants under stress. Target pest must be completely covered with spray. Check label for list of plants that can be treated. May cause injury to flowers. |
B. |
horticultural
oil4
(Ultra-Fine Oil)
(SafTSide)
(JMS Stylet Oil)
|
Whitmire MicroGen
Brandt
JMS Farms
|
12
4
4
|
—
—
—
|
Use as above for neem oil. Also, do not use with sulfur fungicides; check label for tank mix restrictions. |
organochlorine |
A. |
endosulfan*
(Endosulfan 3EC)
|
Drexel |
48 |
2A |
Check local
water/runoff restrictions. Some varieties of chrysanthemum exhibit phytotoxicity. Do not apply more than 3 lb a.i./ acre/season. |
phenoxypyrazole |
A. |
fenpyroximate
(Akari)
|
SePRO |
12 |
21A |
Do not apply
more than 10 gal spray/1000 sq ft/application. Do not exceed 48 oz/crop cycle or growing season, whichever is longer. |
pyrethroid |
A. |
bifenthrin
(Attain TR)
|
Whitmire
MicroGen
|
12 |
3 |
Check label. A fogger for greenhouse use only. |
B. |
bifenthrin*
(Talstar Professional)
|
Whitmire
MicroGen
|
12 |
3 |
Label permits low-volume application. |
C. |
fenpropathrin*
(Tame 2.4EC Spray)
|
Valent |
24 |
3 |
Label permits low-volume application. |
D. |
fluvalinate
(Mavrik Aquaflow)
|
Wellmark |
12 |
3 |
Label permits low-volume application. Also labeled as a cutting dip at 5 fl oz/100 gal. |
pyridazinone
|
A. |
pyridaben
(Sanmite 75WP)
|
BASF |
12 |
21A |
Use at least 2
different chemicals between applications of Sanmite. Do not use fertilizers containing boron. Do not exceed 10.67 oz/acre/application. |
pyrrole |
A. |
chlorfenapyr
(Pylon)
|
OHP |
12 |
13 |
Greenhouse use only. Do not exceed 3 applications/growing cycle. |
soap3 |
A. |
potash soap#
(M-Pede)
|
Dow Agro
Sciences
|
12 |
— |
Must contact
mite, so thorough coverage is important. Repeat weekly as needed up to 3
times. Test for phytotoxicity. Do not spray new transplants or newly rooted cuttings. Do not add adjuvants. |
spinosyn |
A. |
spinosad
(Conserve SC)
|
Dow Agro
Sciences
|
4 |
5 |
Miticidal
activity of this material is due mainly to the surfactants and other inert
ingredients. This material is not recommended for use against mites unless
control is also needed for other pests (caterpillars, leafminers, thrips)
against which the active ingredient in this product is effective. Do not
apply more than 10 times in a 12-month period. Compatible with most beneficials
but highly toxic to bees and hymenopteran parasites. Direct contact can cause
significant mortality to Phytoseiulus
persimilis.
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UC IPM Pest Management Guidelines: Floriculture and Ornamental Nurseries
UC ANR Publication 3392
Insects and Mites
J. A. Bethke, Entomology, UC Riverside
Acknowledgment for contributions to Insects and Mites:
K. L. Robb, UC Cooperative Extension, San Diego County
H. S. Costa, Entomology, UC Riverside
R. S. Cowles, Connecticut Agricultural Experiment Station, Windsor, CT
M. P. Parrella, Entomology, UC Davis
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