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How to Manage Pests
UC Pest Management Guidelines
Citrus
Katydids
Scientific Names:
Forktailed bush katydid: Scudderia furcata
Angularwinged katydid: Microcentrum retinerve
(Reviewed 7/03,
updated 7/05)
In this Guideline:
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DESCRIPTION OF THE PESTS
Katydids resemble
grasshoppers but have long antennae. Nymphs are wingless and
have black and white banded antennae. Females of the forktailed katydid lay
gray, oval, flat eggs in leaves where they have been feeding. Nymphs appear in
April and May and take 2 to 3 months to mature. Angularwinged katydids are
larger than forktailed katydids, have broader wings and have a humpback appearance
both as nymphs and as adults. Females lay their gray, oval eggs in two
overlapping rows on twigs and leaves. Katydids have only one generation a year.
DAMAGE
Of the two species feeding on citrus, only the forktailed katydid
causes economic damage. This species feeds on young fruit at petal fall with
subsequent buildup of scar tissue and distortion of
expanding fruit. Katydids take a single bite from a fruit and then move to
another feeding site on the same or nearby fruit. In this way, a few katydids
can damage a large quantity of fruit in a short time. They also eat holes in
leaves and maturing fruit, creating injury that resembles damage by citrus
cutworm. The angularwinged katydid is less abundant than the forktailed katydid
and feeds only on leaves.
MANAGEMENT
Look for eggs laid inside edges of leaves in fall to detect
infestations of forktailed bush katydids. In orchards with good biological
control, parasites often attack katydid eggs. In spring when monitoring for
orangeworms, also check for katydid damage. With the reduced use of
organophosphate and carbamate insecticides, katydids have become more numerous.
Larger instars are not well controlled by cryolite or spinosad. If you find
katydids in an orchard with high previous katydid damage, especially at petal
fall, treatment is recommended and can be applied in combination with treatment
for citrus thrips. Tank mixing organophosphates (naled, chlorpyrifos) or
pyrethroids (cyfluthrin, fenpropathrin) with spinosad applied for citrus thrips
helps to simultaneously control katydids.
| Common name |
Amount to Use |
Minimum Days before
Harvest+
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| (trade name) |
(type of coverage)** |
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| A. |
CRYOLITE |
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(Prokil Cryolite) 96 |
8–20 lb/acre (OC) |
15 |
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(Kryocide) 96 WP |
8–20 lb/acre (OC) |
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RANGE OF ACTIVITY:
Narrow (foliage feeders such as worms, katydids, and Fuller rose beetle).
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PERSISTENCE:
Long, unless washed off by rain.
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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 katydids. Do not exceed 90 lb/acre/season.
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| B. |
DIFLUBENZURON* |
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(Micromite) 80 WG |
3.125–6.25 oz |
21 |
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RANGE OF ACTIVITY:
Narrow (katydids, peelminer, grasshoppers)
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PERSISTENCE:
Short
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COMMENTS: Can be used during bloom. Timing treatments for
peaks in moth flights is important because it only kills the egg stage of the
peelminer. Apply by ground application using 50-200 gallons of water per
acre. Do not apply more than 6.4 oz per 90 day period or 18.75 oz per year.
Do not apply within 25 feet of bodies of water. Use allowed under a FIFRA
2(ee) recommendation.
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| C. |
SPINOSAD |
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(Entrust)# |
1.25–3 oz/acre (OC) |
1 |
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(Success) |
4–6 fl oz/acre (OC) |
1 |
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RANGE OF ACTIVITY:
Narrow (citrus thrips, katydids, orangeworms)
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PERSISTNENCE: Short |
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COMMENTS: Most effective in controlling young stages of
katydids.
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| D. |
NALED |
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(Dibrom) 8E |
1–2 pt/acre (OC) |
7 |
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RANGE OF ACTIVITY:
Broad (insects and beneficial mites)
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PERSISTENCE:
Intermediate
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COMMENTS: For use on oranges, grapefruit, lemons, and
tangerines. Apply at petal fall.
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| E. |
CHLORPYRIFOS* |
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(Lorsban) 4EC |
2–8 oz/acre (A) |
21 |
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...or... |
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2–8 oz/acre (OC) |
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RANGE OF ACTIVITY:
Broad (insects and beneficial mites)
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PERSISTENCE:
Intermediate
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COMMENTS: For use on all varieties. No more than 2
applications/year with at least 30 days between applications. Do not apply
during daylight hours of bloom period.
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| F. |
DIMETHOATE 4 |
0.5–2 pt/acre (OC) |
15 |
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RANGE OF ACTIVITY:
Broad (insects and beneficial mites)
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PERSISTENCE:
Long
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COMMENTS: For use on oranges, grapefruit, lemons, and
tangerines.
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| G. |
CYFLUTHRIN* |
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(Baythroid) 2E |
6.4 fl oz/acre (OC) |
12 hours |
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RANGE OF ACTIVITY:
Broad (insects and beneficial mites)
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PERSISTENCE:
Long
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RESISTANCE: In some citrus thrips populations in the San
Joaquin Valley
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COMMENTS: Only a single application may be made per crop
season. To reduce the potential for resistance, make a total of only one
pyrethroid application (for all pest species) per year. Do not apply within
25 feet of lakes, reservoirs, rivers, permanent streams, marshes, or natural
ponds, estuaries, and commercial fish farm ponds.
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| H. |
FENPROPATHRIN* |
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(Danitol) 2.4EC |
21.33 fl oz/acre (OC) |
1 |
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RANGE OF ACTIVITY:
Broad (insects and mites)
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PERSISTENCE:
Long
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RESISTANCE: In some citrus thrips populations in the San
Joaquin Valley
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COMMENTS: Apply in 50–200 gal water/acre. Use only on citrus
trees 3 years or older. To reduce the potential for resistance, make a total
of only one pyrethroid application (for all pest species) per year. Do not
apply in the vicinity of aquatic areas, and do not apply more than 21.33 fl
oz/acre/year.
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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. O’Connell, 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
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