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How to Manage Pests
UC Pest Management Guidelines
Apple
Stink
Bugs
Scientific Names:
Consperse stink bug: Euschistus conspersus
Conchuela: Chlorochroa ligata
Redshouldered stink bug: Thyanta pallidovirens
(Reviewed 8/06,
updated 3/09)
In this Guideline:
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Stink bugs and other plant bugs occur in all of California, but only
reach damaging numbers sporadically. Although they may differ in color and
size, stink bugs have the same overall shield-shaped body. The consperse stink
bug is the most common. Adult consperse stink bugs have gray brown to green
bodies with yellow to orange legs and antennae that have darkened tips. The
body and legs are covered with small black specks and the undersurface of the
body varies from gray to green. Consperse stink bug eggs are laid in clusters on twigs and leaves. They are barrel-shaped, pearly white
when first laid, turning pink before hatching. The conchuela is a large black
stink bug with a reddish marginal border and a reddish spot in the middle of
the back. Redshouldered plant bugs are green or brown stink bugs that may have
a red line across the shoulder.
Stink bugs damage the crop directly by feeding on fruit. Early season feeding results in dimples
or irregularly depressed areas on mature fruit. If the feeding occurs after
maturity there is little external evidence other than excrement, which appears
as small, brown, tear-shaped drops. Internally, stink bug feeding produces
white, pithy areas that turn brown when fruit is peeled. If the spots are the result of stink bug
feeding, these pithy areas will be concentrated near the stem end of the fruit.
If they resulted from lygus bug feeding, they may be located anywhere on the fruit surface. Adult stink bugs
move from tree to tree and can puncture large numbers of fruit. If they are
migrating into the orchard, fruits on trees in outside rows will show the most
damage. Frequently, damage by these pests is limited to specific areas in the
orchard. If the infestation is very heavy, however, the entire crop can be
damaged.
Infestations of stink bugs depend on the type of vegetation in and
adjacent to the orchard. Most infestations occur in orchards with ground covers
or adjacent to uncultivated areas; stink bugs move to ground covers in orchards
when weeds in uncultivated areas dry. Consperse stink bug is rarely a pest in
clean-cultivated orchards surrounded by cultivated lands, unless the land is
planted in crops stink bugs favor: wheat, tomatoes, berries, alfalfa, or corn.
Cultural Control
Eliminate
weed host plants listed above both within and adjacent to the orchard to
minimize stink bug problems. Do not mow cover crops or weeds when stink bugs
are present or they will move into the trees.
Organically Acceptable Methods
Cultural
control is organically acceptable.
Monitoring and Treatment Decisions
Monitor for
stink bugs in March or April by inspecting host plants located inside and along
borders of sampling blocks. Spend about an hour checking the bases of plants
for overwintered adult bugs. Favored host plants are mullein,
mustard,
and dock.
If these are not present, bugs may be found on plantain,
milkweed, mallow,
morningglory,
thistles, vetch, velvetgrass, breadgrass,
bushberries, everlasting peas, and other broadleaf plants. If more than five bugs
are found during the hour, spray the weeds with an insecticide immediately.
Depending on the distribution of the bug population, a spot treatment may be
adequate. If two to five bugs are found and bug damage has been experienced
previously in the orchard, spraying the weeds might be advisable. If fewer than
two bugs are found, resample in 7 to 10 days.
Sample for adults or damaged fruit in June and July. Take a
50-tray beating sample for each 20-acre block, taking most of the samples from
border trees to locate bugs flying in from adjacent fields. If one or more bugs
are collected, inspect fruit for feeding damage. Either examine fruit on the
tree for the presence of bugs, excrement, or visible damage, or collect fruit
from the lower half of the tree and peel it. If more than three fruits per half
hour of inspection show feeding damage, spots of excrement, or active bugs, or
there is one damaged fruit per 100 peeled, treatment of trees probably is
required to avoid economic loss by end of harvest.
| Common name
|
Amount to use** |
R.E.I.+
|
P.H.I.+
|
| (trade name) |
(conc.) |
(dilute) |
(hours) |
(days) |
|
| When choosing a pesticide, consider
information relating to the impact on natural enemies and
honey bees
and environmental impact. |
| |
| PINK BUD
to BLOOM |
| Note: Apply as a thorough, drenching ground spray to cover crop; use 100–300 gal water/acre. |
| A. |
FENPROPATHRIN* |
| |
(Danitol) 2.4EC |
16–21.33 fl oz |
4–5.44 fl oz |
24 |
14 |
| |
MODE OF ACTION GROUP NUMBER1: 3 |
| |
COMMENTS: Begin applications when first pest activity is noticed. Use higher rate under severe insect pressure. |
| |
|
| B. |
DIMETHOATE E267 |
— |
Label rates |
48 |
28 |
| |
MODE OF ACTION GROUP NUMBER1: 1B |
| |
COMMENTS: Do not apply during bloom. Harmful to beneficial mites. |
| |
|
| C. |
FORMETANATE HYDROCHLORIDE |
| |
(Carzol) SP |
— |
4 oz |
16 days |
0 |
| |
MODE OF ACTION GROUP NUMBER1: 1A |
| |
COMMENTS: Do not apply more than 1.25
lb/acre/season. Do not apply after petal fall. See label for second application restrictions. |
| |
|
| D. |
ENDOSULFAN* |
| |
(Thionex) 3EC |
— |
1.33 pt |
24 |
30 |
| |
MODE OF ACTION GROUP NUMBER1: 2A |
| |
COMMENTS: Do not apply near bodies of water
containing fish. Stink bugs may be resistant to endosulfan. Maximum of 3.5 qt/acre. |
| |
|
| MAY/JUNE to PREHARVEST |
| Note: Apply to trees |
| A. |
FENPROPATHRIN* |
| |
(Danitol) 2.4EC |
16–21.33 fl oz |
4–5.44 fl oz |
24 |
14 |
| |
MODE OF ACTION GROUP NUMBER1: 3 |
| |
COMMENTS: Begin applications when first
pest activity is noticed. Use higher rate under severe insect pressure. Disruptive of natural enemies. |
| |
|
| B. |
DIMETHOATE |
Label rates |
48 |
28 |
| |
MODE OF ACTION GROUP NUMBER1: 1B |
| |
COMMENTS: Harmful to beneficial mites. |
| |
|
| C. |
ENDOSULFAN* |
| |
(Thionex) 50WP |
4 lb |
1 lb |
4 days |
30 |
| |
MODE OF ACTION GROUP NUMBER1: 2A |
| |
COMMENTS: Do not apply near bodies of water
containing fish. Stink bugs may be resistant to endosulfan. Maximum of 3.5 qt/acre. |
| |
|
| ** |
For
dilute application, rate is per 100 gal water to be applied in 300-500 gal
water/acre, according to label; for concentrate applications, use 80–100 gal water/acre or lower if the label allows. |
| + |
Restricted
entry interval (R.E.I.) is the number of hours (unless otherwise noted) from
treatment until the treated area can be safely entered without protective
clothing. Preharvest interval (P.H.I.) is the number of days from treatment
to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest. |
| * |
Permit required from county agricultural commissioner for purchase or use. |
| — |
Not recommended or not on label. |
| 1 |
Rotate
chemicals with a different mode-of-action Group number, and do not use
products with the same mode-of-action Group number more than twice per season
to help prevent the development of resistance. For example, the organophosphates
have a Group number of 1B; chemicals with a 1B Group number should be
alternated with chemicals that have a Group number other than 1B. Mode of
action Group numbers are assigned by IRAC (Insecticide Resistance Action
Committee). For additional information, see their Web site at http://www.irac-online.org/. |
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UC IPM Pest Management Guidelines: Apple
UC ANR Publication 3432
Insects and Mites
J. L. Caprile, UC Cooperative
Extension, Contra Costa County
L. R. Wunderlich, UC Cooperative Extension, El Dorado County
P. M. Vossen, UC Cooperative Extension, Sonoma and Marin counties
W. W. Coates, UC Cooperative Extension, San Benito County
H. L. Andris, UC Cooperative Extension, Fresno County
L. G. Varela, UC IPM Program, Sonoma County
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
Acknowledgment for contributions to Insects and Mites:
C. Pickel, UC IPM Program, Sutter and Yuba counties
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