Grub Damage Research Articles

Grass grub damage in irrigated and dryland pastures near Carew, mid Canterbury

Grass grub damage in irrigated and dryland pastures near Carew, mid Canterbury

Pasture management and pasture species for improved dry matter production in south Taranaki

Dry matter (DM) production and seasonal distribution of old ryegrass/white clover pasture defoliated at 14- and 28day intervals, and new sowings of 'Grasslands Maru' phalaris (Phaluris aquatica L.), 'Grasslands Roa' tall fescue (Festuca arundinacea Schreb.), and 'Grasslands Kara' cocksfoot (Dactylis glomerata L.) at 28day defoliation intervals were evaluated in an environment prone to grass grub damage and dry summer/autumn periods. Under a 28&y defoliation interval old ryegrass produced 2O%more DM that the 14-day defoliation interval, the difference occuring mainly in spring. Annual production, in the initial 4 years, of phalaris and tall fescue was respectively 17 % and 20 % more than that of old ryegrass. Phalaris was superior to old ryegrass in all seasons. Cocksfoot annual production was similar to that of old ryegrass, producing more in summer (9%) and autumn (19%) but 15% less in spring. Results from year 5 and 6 suggest that phalaris may not be as persistent as tall fescue. A 28-day rotation in spring is recommended to maximise production of old ryegrasslclover pasture. Phalaris and tall fescue are recommended as alternative species to old ryegrass in a grass grub prone and/or summer dry environment. Cocksfoot is not recommended. Keywords pasture production, seasonal distribution, cow requirements, old ryegrass, phalaris, tall fescue, cocksfoot

An ‘Insecticide test plot’ technique for early detection of pasture damage by grass grub,Costelytra zealandica(White) (Coleoptera: Scarabaeidae)

A technique is described in which fensulfothion insecticide was applied in mid-late summer to plots of pasture for early detection of damage by grass grub (Costelytra zealandica). A trial which tested this technique on three sites near Riversdale, Southland in 1985 showed that there was an inverse relationship between grass grub density and the number of days before pasture damage became visible. The best time to establish the insecticide plot for early warning of potential grub damage was January. Further trials in 1986, where test plots were established in January over a range of sites with different grass grub densities, demonstrated that the technique would allow farmers to recognise a potential loss of pasture as a result of grass grub up to 6 weeks before they would otherwise have done so, and take remedial action or modify their pasture management to compensate.

Wireworm and White Grub Control in Potato, 1987

Abstract Wireworm control trials were established at 3 locations in Minnesota: Staples (Wadena County), Itasca (Clearwater County), and Woodbury (Washington County). All sites had either old alfalfa-grass or pasture as the previous crop. Soils were sandy loam and irrigated at Wadena County, clay loam and very moist in Clearwater County, and sandy loam with a spring drouth in Washington County. Severe white grub infestations developed at the Washington and Clearwater locations. A large wireworm population was present in Washington; neither was found in Wadena. The latter permitted evaluation of uncomplicated chemical effects on the potato itself. Insecticides were applied in the furrow with the seed piece in Wadena and Clearwater and over the planted row and then lightly covered in Washington. Plots were single rows 50 ft long, replicated 6 times at each site, and arranged in a randomized complete block design. A different design was used at each location. Fungicide and foliar insecticides were broadcast on all plots at least 3 times at each location to protect the growing potato throughout the season. Plots were hand dug and all tubers were examined and separated according to grub damage, wireworm damage, damage by both, and no damage. Percent effect for each case was calculated and transformed by ARCSINE, and the means were compared.

Evaluation of Nematic1Des/Insecticides for Sweet Potato, Wayne County, 1978

Abstract The effects of fumigant and non-fumigant nematicides/insecticides on nematodes and soil insects, yield, and quality of sweet potatoes were studied in a deep Norfolk sandy loam (pH = 6.4; O. M. = 0.5%; sand = 85.2%, silt = 10.1%, clay = 4.7%) in Wayne County, NC. The site had been planted to sweetpotatoes in 1977 and soybeans in 1976; root-knot nematode larvae counts of ca. 100/500 cm3 soil were low on May, 1978. On Jun 7, plots were hilled, and Vernam 6EC herbicide (.66 pt/acre) was applied. On Jun 14, fumigants were injected with a single chisel at a depth of ca. 6 inches centered over the row using a self-propelled applicator. Soil temperature at 6-inch depth was 83°F, air temperature was 90°F, and soil moisture was 85.3% of field capacity. On Jun 28, granular formulations were uniformly applied with a “salt shaker#x201D;, and wettable powders were suspended in water and applied as a drench at a rate of ca. 500 gal/acre or were applied with transplant water. Granular materials and drenches were applied to a 12-inch band over row centers, and within an hour incorporated to a depth of ca. 6-8 inches using a rototiller. Soil temperature at a 6-inch depth was 88°F, air temperature was 95°F, and soil moisture was fairly dry (77.6% of field capacity). On Jul 24, at layby, granular materials were uniformly applied to a 12-inch band over plant canopy using a “salt shaker#x201D;. Plots were single rows, 50-ft long, on 40-inch spacing. Treatments were replicated in four complete randomized blocks with 10-ft alleys between replications. On Oct 23, twelve soil borings (2 to 12-inch horizon) were taken from the root zone of each plot, composited, assayed for nematodes (extracted by the elutriation-centrifugation technique) and identified. On Oct 24, roots were harvested, graded into U.S.D.A. size grades (Jumbo, No. 1, Conner), and weighed; fifteen roots (5 canner, 5 small and 5 medium No. 1) were removed from each plot and rated for nematode, wireworm, white grub, and flea beetle damage; internal nematode infection was counted by slicing ca. 40% of the distal portion of each root in 2-mm sections and counting internal lesions. Weather during growing season was dry, and plants were under moisture stress in late summer. There was no water injury to roots at harvest as had occurred in previous years.

A farmlet study of the effects of grass grub damage in the Takapau district of central Hawkes Bay

A farmlet study of the effects of grass grub damage in the Takapau district of central Hawkes Bay

Effects of grass grub (Costelytra zealandicawhite) larvae on pasture plants

Abstract Perennial ryegrass Lolium perenne L.) was established in a pot and field trial with and without mineral fertiliser and 60 third-instar grass grubs (Costelytra zealandica White) per 30 cm2, for 86 and 93 days respectively. Fertilisers stimulated shoot growth by 30% in the pot trial and 90% in the field trial. In both trials 60 grass grubs per 30 cm2 induced a 10% depression in total shoot growth. Smaller shoot yields in treatments with grass grubs were associated with slightly lower levels of P, K, and N in the herbage. Root yields in pots were depressed by grass grubs at both levels of fertility, but in the field this depression occurred only in the fertilised treatment. There were no treatment differences in grass grub survival.

Susceptibilities of European Chafer and Japanese Beetle Grubs to Chlordane and Dieldrin: Suggesting Reductions in Application Rates1

Laboratory tests were conducted to compare the relative susceptibilities of the European chafer, Amphimallon majalis (Razoumowsky), and the Japanese beetle, Popillia japonica Newman, as 1st- and 3-instar larvae to chlordane and dieldrin. As 1st instars, it required >1.46 ppm chlordane and 0.84 ppm dieldrin to eliminate the chafer compared with 1.25 ppm chlordane and <0.21 ppm dieldrin to eliminate the Japanese beetle. Grubs were more susceptible at fluctuating temperatures than at a constant temperature. As 3rd instars, it required 1.6 times more chlordane and 2.3 times more dieldrin to produce comparable results in the European chafer as in the Japanese beetle. Lawn plots harboring mixed populations of the 2 species were treated with 4 levels each of chlordane and fielding during June 1968. Fall surveys 4 months later showed that both species were equally susceptible to fielding. European chafer grubs were more susceptible to chlordane than Japanese beetle grubs. From the results of I season, it appears that rates of application for protecting lawns against grub damage can be lowered from the currently recommended 11.2 kg/ha of chlordane and 3.4 kg/ha of dieldrin (equivalent to 10 and 3 lb/acre, respectively) to 4.5 and 1.1 kg(ha rates (equivalent to 4 and 1 lb(acre) for both species.

Poly-phylla fullo L. (Col., Melolonthidae) in the dunes.

It is possible to reduce the loss of young saplings to a third by dipping the roots in aldrin emulsion before planting; addition of aldrin dust to the planting hole will eliminate almost all grub damage. Fairly good results follow if this treatment is combined with narrow spacing to ensure quick plant cover; vegetative growth might be hastened by fertilizing. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Aphodius pardalis Lec. A New Turf Pest12

In April, 1954, grub damage to golf fairways at Eugene, Oregon, was called to the attention of the writers by Mr. Howard, greenskeeper of the Eugene Country Club. He indicated that some 125 to 150 acres of turf were affected. Grubs found beneath the injured sod were identified as Aphodius spp.

GRASS GRUB CONTROL

Farmers throughout New Zealand agree that grass grubs, or the larvae of Odontria zealandica, are the most serious insect pests of pasture. Though damage is not conspicuous every year in established pasture, there is usually a certain amount of annual thinning out of valuable fodder plants and their replacement by weeds such as plantain, dandelion, mouseeared chickweed, and weed grasses such as sweet vernal and hair grass. It is difficult to estimate losses involved in this way except by close inspection of pastures or by a fall in farm returns. For example, one dairy farm in the Waikato produced over 80001b. less butterfat this :year than last, and yet it was only after a careful mspection that it was found that these pastures-though they looked uniform from a distance- had deteriorated by approximately one third. Though no definite sequence of grass grub damage can be predicted, it is common for an infestation to build up over a period ranging from 1 to 8 years, with damage becoming progressively worse from an original patchy effect till the pasture is more or less uniformly infested.