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General Turf Insects – Thatch and Soil Pests. David J. Shetlar, Ph.D. The “BugDoc”. The Ohio State University, OARDC & OSU Extension Columbus, OH. © October, 2002, D.J. Shetlar, all rights reserved. Thatch & Soil Pests. Sucking Pests Ground Pearls Root Aphids. Chewing Pests
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General Turf Insects – Thatch and Soil Pests David J. Shetlar, Ph.D. The “BugDoc” The Ohio State University, OARDC & OSU Extension Columbus, OH © October, 2002, D.J. Shetlar, all rights reserved
Thatch & Soil Pests Sucking Pests Ground Pearls Root Aphids Chewing Pests White Grubs Mole Crickets
Annual White Grub Species • Masked Chafers(North America - N, S, SW, W, SE) • Japanese Beetle(eastern NA) • Oriental Beetle (northeastern NA) • European Chafer(northeastern NA) • Asiatic Garden Beetle(northeastern NA) • Green June Beetle(south-transition NA) • May/June Beetles(southern only)
White Grub Adults Annual Grubs GJB, EC, SMC, NMC, JB, OB, AGB Multi-year Grubs,M/JB Multi-gen/yr Grub,BTA
Annual Grubs GJB, EC, MC, JB, OB, AGB Multi-year Grubs,M/JB Multi-gen/yr Grub,BTA White Grub Third Instars
Japanese beetle has V-shaped pattern. Identifying Grub Species • Identify grubs by raster pattern • Adults are easy to ID but they don’t predict grub populations!
Japanese beetle adult skeletonizing leaf Mating cluster of beetles in turf Japanese Beetle –
Japanese Beetle Life Stages egg 1st 2nd 3rd pupa adult instar larva
Japanese Beetle Annual Cycle JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Pair of masked chafers at night on turf Masked chafer eggs newly laid (below) 48 hours in moist soil (above) Masked Chafers –
Identifying Grub Species Masked chafers have no pattern!
Northern Masked Chafer Southern Masked Chafer Southwestern Masked Chafer Western Masked Chafer Masked Chafer Distribution Maps
Northern Masked Chafer Life Stages egg 1st 2nd 3rd pupa adult instar larva
Mature grub “crawling” on soil Adult Green June Beetle – Overwintering Japanese beetles Grub in overwintering burrow
Identifying Grub Species GJB grubs crawl on their backs!
Soil mounds around burrows in fall. Note thinning of turf where grubs have come to the surface to feed. Spring “clean-out” mounds from green June beetles on a golf course fairway.
Adult © H. Niemczyk European chafer adults swarming to tree at dusk for mating European Chafer –
Identifying Grub Species European chafers have Y-shaped anus & two rows of bristles that diverge at anus. Y-shaped anus with two rows of bristles.
Three common color forms of Oriental beetle Asiatic garden beetles feeding & mating Oriental Beetle & Asiatic Garden Beetle –
Identifying Grub Species Oriental beetle has two rows of small spines, 12-15 in number. Asiatic garden beetle has vertical anus & broad U-shaped spine pattern.
Oriental Beetle & Asiatic Garden Beetle Distribution Maps Oriental Beetle (2000) Asiatic Garden Beetle (2000)
BTA adults have a smooth hind tibia while Aphodius has three spurs.
Identifying Grub Species Ataenius raster is random pattern of bristles and anal pads separate. Aphodius raster has small V pattern and anal pad is only cleft, not divided.
Black Turfgrass Ataenius Distribution Aphodius granarius is mainly northern in distribution.
BTA damage first appears as turf that wilts in the afternoon heat, but recovers when irrigated. A few days later, the turf will not recover for more than a day or several hours. At this point it is near death!
Turf killed by BTA larvae in late June and early July. These patches can continue to expand, so rapid action is essential for saving the turf!
May/June Beetles, Phyllophaga – Most Phyllophaga are listed as being multiple-year life cycle species, but many of the southern species are annual grubs. Adult Phyllophaga commonly feed on the leaves of local trees.
Identifying Grub Species Phyllophaga grubs generally have two parallel rows of bristles DO NOT diverge at the anus (like European chafers).
Diagram of a Phyllophaga species with a three-year life cycle. Note that the adults are formed in September and overwinter in their last year of development.
© HDN © HDN Target Principle
Where do grubs feed? Ans: Soil-Thatch Interface © HDN
Ans: THATCH, soil (oh, and roots) What do grubs eat?
Northern Masked Chafer Life Stages Egg Larva Pupa Adult 1st 2nd 3rd Instar NOTE: if the first instar grub is “one unit” of weight, the second instar is about 15 to 20 units and the third instar is 35 to 50 units.
A study in California to determine the relative susceptibility of masked chafer first, second and third instar grubs to an insecticide, diazinon in this case. They found the following relative susceptibility of these instars: • First Instar – 1 unit • Second Instar – 26 units • Third Instar – 120 units! Therefore, grub susceptibility to insecticides does not appear to be a “straight line” effect of body weight!
Preventive-Early Curative Timing Traditional Control Timing Japanese Beetle Annual Cycle JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
rate ave range % of tests Insecticide lb.ai . /a. % control # tests % control below 70% Thiamethoxam 0.2 96.1 38 0-100 3 (=Meridian) Halofenozide 92.8 1.5 57 10-100 10 (=MACH2) Imidacloprid 93.7 0.3 58 58-100 7 (=Merit) Trichlorfon 77.6 8.0 90 0 -98 19 (=Dylox, Proxol) Carbaryl 74.3 8.0 40 13-100 37 (= Sevin) Diazinon 69.0 4.0 20 47-99 42 74.8 5.5 41 25-100 29 Chlorpyrifos 54.6 4.0 32 0-96 59 (=Dursban) Ranked Efficacy of White Grub Insecticides 1976 – 2001a a Data from ESA publications (1977-2001) using masked chafer and Japanese beetle data where label timing recommendations were used and at least 4.0 grubs per sq.ft. were found in checks.
Comparison of Grub Insecticide Efficacy by Time of Application rate ave % control (#tests) Insecticide lb.ai./a. May June July to Aug 16 to Sept 10 Halofenozide 1.5 92.8 (6) 96.8 (18) 92.2 (15) 92.0 (13) 80.3 (22) (=MACH2) Imidachloprid 0.3 90.2 (8) 91.8 (16) 94.9 (16) 95.6 (17) 96.5 (29) (=Merit) Thiamethoxam 0.2 80.0 (5) 98.8 (11) 98.6 (9) 98.3 (11) 93.7 (8) (=Meridian) 0.26 91.5 (4) 99.3 (3) 99.3 (2) 98.0 (6) 100.0 (4) Trichlorfon 8.0 --- --- --- 91.0 (2) 83.3 (12)
Tawny Mole CricketScapteriscus vicinus Scudder Southern Mole CricketS. borellii Giglio-Tos (=S. acletus Rehn & Hebard) Short-winged Mole Cricket S. abbreviatus Scudder Native Mole Cricket Gryllotalpa hexadactyla Perty Mole Crickets