|
|
How to Manage Pests
UC Pest Management Guidelines
Citrus
Fuller Rose Beetle
Scientific Name: Asynonychus godmani
(Reviewed 7/03,
updated 7/05)
In this Guideline:
|
|
|
DESCRIPTION OF THE PEST
Adult Fuller rose beetles
are brown snout beetles. They can be distinguished from two
other snout beetles that occur in California citrus groves but do not cause
damage: viewed from the top the Fuller rose beetle head and bulging eyes are
different than the cribrate weevil, which has a teardrop-shaped head with
closely spaced eyes, and viewed from the side the Fuller rose beetle's snout is
less sharply pointed to the ground than that of the vegetable weevil.
The beetle has one generation a year. Eggs are laid in a mass
of several dozen on fruit, especially underneath the button or in cracks and
crevices in the tree. When eggs hatch, larvae drop to the ground
and live in the soil where they feed on roots of citrus for 6 to 10 months.
They pupate in the soil and the adults emerge 1.5 to 2 months later. Adults are
flightless and reach the canopy by climbing up the trunk or branches that touch
the ground or vegetation.
DAMAGE
The beetle itself does not generally cause economic damage in citrus
but the presence of eggs on fruit exported to Japan will require that the
shipment be fumigated. Fumigation is expensive and is especially damaging to
lemons. Fuller rose beetle adults feed along the margins of citrus leaves,
creating notches and leaving a characteristic sharp, ragged
appearance.
MANAGEMENT
If management of Fuller
rose beetles is necessary, there are three primary strategies: (1) skirt
pruning with trunk treatment; (2) preharvest foliar sprays, or (3) season-long
suppression with foliar sprays for 1.5 to 2 years. Use skirt pruning and trunk
treatment in orchards with a history of Fuller rose beetle. As an alternative,
one or two preharvest foliar sprays may be applied to prevent exported fruit
from being infested with viable eggs.
Biological Control
The egg parasite, Fidiobia citri, can parasitize up to 50% of each egg mass. Parasitized eggs are a dark gold
color and they may persist long after unparasitized eggs have hatched.
Cultural Control
If Fuller rose beetle has been a problem in your orchard in the past,
the best strategy is to prevent the flightless adults from reaching the canopy
by using skirt pruning and trunk treatments. Skirt prune trees 24 to 30 inches
above the ground to prevent adults from reaching the canopy and apply sticky
material to the trunk. Sticky material can be expected to last 2 to 10 months,
depending on wash-off by sprinklers and the amount of dirt and leaf
contamination. Sticky material will also control ants, and if it contains
tribasic copper sulfate, it is effective against brown garden snail as well.
Some concern has been expressed regarding the application of
sticky polybutene materials directly to the trunk of citrus trees, especially
if multiple applications are applied to the same area of the trunk. The sticky
material can be applied on top of a tree wrap but this is both laborious and
expensive. Trials to date have failed to show serious phytotoxicity (minor bark
cracking has been seen in a very small number of cases) except in situations
where damage is associated with sunburn—i.e., where the banded area is exposed
to direct sunlight (especially a concern on topworked trees or on young trees
which have a very thin cambium layer and are more susceptible to damage). Do
not apply sticky materials to young or topworked trees.
Organically Acceptable Methods
Biological and cultural controls, including the application of sticky
materials are acceptable organic methods.
Monitoring and Treatment Decisions Degree-day calculator
Degree-day table
If Fuller rose beetle damage occurs in an orchard, sample for adults
from July to November by shaking or beating branches onto a sheet or tray. If
beetles are found, sample fruit for egg masses, especially in the areas where
adult feeding damage has been found. Sample a minimum of 500 fruit in a 10 acre
block (5 fruit per tree from 10 trees per acre). Select fruit from chest height
from a different quadrant of the canopy. Clip the stem 2 inches from fruit,
then hold the stem and twist off the button. Look for egg masses on the underside
of the button end and on the fruit where it was covered by the button. If the
fruit is to be shipped to Japan, infestation levels should be less than one
fruit infested with a viable, unhatched egg per 1,000 fruit sampled at harvest.
Treat 600 degree-days (accumulated above 51°F lower threshold)
before harvest. (For assistance in calculating degree-days, see "Degree-days"
on the UC IPM Web site at www.ipm.ucdavis.edu.) This can range from 1 to 4
months, depending on the weather. During cool weather, retreatment may be
necessary.
| Common name |
Amount to Use |
Minimum Days before
Harvest+
|
| (trade name) |
(type of coverage)** |
|
|
| A. |
STICKY POLYBUTENE MATERIALS# |
2- to 4-inch band |
|
| |
RANGE OF ACTIVITY:
Narrow (trunk climbers)
|
| |
PERSISTENCE:
Long
|
| |
COMMENTS: For use on all varieties. Use polybutene-based
products only. Do not apply sticky materials directly on the trunk of young
or topworked trees where the treated area is exposed to the sun—in these
cases, use a 6- to 18-inch wrap under the sticky material to protect the tree
from sunburn. Exercise caution in applying multiple applications (more than 3
or 4)—watch for symptoms of bark cracking. Apply the sticky band high enough
to avoid sprinklers, dust, and direct sunlight. Reactivate periodically by
rubbing with a stick to remove dust. Check to ensure that hanging branches,
sticks, weeds, etc. are not allowing Fuller rose beetles access to trees.
|
| |
|
| B. |
CRYOLITE |
|
|
| |
(Prokil Cryolite) 96 |
20 lb/acre (TDC) |
15 |
| |
(Kryocide) 96WP |
20 lb/acre (TDC) |
|
| |
RANGE OF ACTIVITY:
Narrow (foliage feeders such as worms, katydids, and Fuller rose beetle).
|
| |
PERSISTENCE:
Long, unless washed off by rain.
|
| |
COMMENTS: Check label for variety. Use higher rate for larger
trees. Slow-acting stomach poison that may take several days of warm weather
to kill Fuller rose beetles. Do not exceed 90 lb/acre/season.
|
| |
|
| C. |
CARBARYL* |
|
|
| |
(Sevin) 80S |
1.2 lb/100 gal (TDC) |
|
| |
(Sevin XLR Plus) 4F |
1 qt/100 gal (TDC) |
5 |
| |
RANGE OF ACTIVITY:
Broad (insects and beneficial mites)
|
| |
PERSISTENCE:
Long
|
| |
COMMENTS: For use on all varieties. Do not exceed 25
lb/acre/application of Sevin 80S or
20 qt/acre/application of Sevin XLR Plus.
|
| |
|
UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441
Insects, Mites, and Snails
E. E. Grafton-Cardwell, Kearney Agricultural Center, Parlier
J. G. Morse, Entomology, UC Riverside
N. V. OConnell, UC Cooperative Extension, Tulare Co.
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura Co.
C. E. Kallsen, UC Cooperative Extension, Kern Co.
D. R. Haviland, UC Cooperative Extension, Kern Co.
Acknowledgments for contributions to the insect, mite, and snail section:
J. Barcinas, E. S. I., Corona, CA
R. Dunn, Badger Farming Co., Exeter, CA
J. Gorden, Pest Management Associates, Exeter, CA
H. Griffiths, E. S. I., Corona, CA
D. Machlitt, Consulting Entomology Services, Moorpark, CA
C. Musgrove, retired entomologist, Riverside, CA
K. Olsen, S & J Ranch, Pinedale, CA
T. Roberts, E. S. I., Corona, CA
J. Stewart, Pest Management Associates, Exeter, CA
P. Washburn, Washburn & Sons Citrus Pest Control, Riverside, CA
Top of page
|