Nematicide Treatments Research Articles

Influence of Acremonium Infection and Pesticide Use on Seasonal Abundance of Leafhoppers and Froghoppers (Homoptera: Cicadellidae; Cercopidae) in Tall Fescue

Resistance to an endophyte, Acremonium coenophialum Morgan-Jones & Gams, and management tactics were evaluated against several leafhopper species under field conditions. ‘Georgia-5’ tall fescue, Festuca arundinacea Schreb., was planted to a randomized block design split plot with a factorial arrangement of pest management treatments in the subplot. Leafhopper and froghopper populations were monitored throughout the year by taking sweep samples approximately every 2 wk. Of the 28 species of leafhoppers and froghoppers collected, 6 species of leafhoppers and 1 species of froghopper comprised over 80% of the specimens collected. With the exception of the nematicide treatment, there was no significant difference in leafhopper population densities due to chemical treatments. Four species of leafhoppers and one species of froghopper showed significantly higher population densities on endophyte-free tall fescue when compared with the endophyte-infected tall fescue plots. The greatest differences between endophyte-free and endophyte-infected tall fescue plots occurred at leafhopper peak seasonal densities. Although chemical treatments apparently have little effect on leafhopper population densities, the Acremonium endophyte provides tall fescue with resistance against some leafhopper species.

INFLUENCE OF SOIL FUMIGANTS AND A NEMATICIDE ON GROWTH AND YIELD OF `MCINTOSH' APPLE TREES ON VARIOUS ROOTSTOCKS

`Rogers Red McIntosh' apple (Malus domestica Borkh.) trees on MM. 111, MM. 106, M.7a, or M.26 were planted in 1984 on an old orchard site, diagnosed with an apple replant disease (ARD) problem. Soil treatments included Telone c-17, Vorlex, Nemacur 3, or not treated. After six years, tree performance problems usually associated with severe ARD did not develop. Lesion nematode [Pratylenchus penetrans (Cobb) Filipjev and Schuurmans-Stekhoven] populations feeding within or on the surface of roots were not affected by nematicide treatments nor rootstocks, even though slightly damaging levels were found in 1986. At the end of the sixth growing season, trunk cross-sectional areas were similar for trees in treated and in untreated soils. Trees on MM. 111 and MM. 106 were the largest, and those on M.26 were the smallest. Cumulative yield was not influenced by soil treatments, but trees on MM. 111 produced the greatest cumulative yields, whereas trees on M.26 were the most yield efficient.

Controlling Apple Replant Disease in `McIntosh' Apple Trees on Various Rootstock

Apple replant disease (ARD) adversely affects development and performance of apple trees planted in old orchard soils; it is characterized by stunted tree growth, which reduces orchard profitability (Hoestra and Oostenbrink, 1962; Mai and Parker, 1967). The probable cause of ARD is a complex of soil-borne microorganisms, including parasitic nematodes. The lesion nematode Pratylenchus penetrans is a component of ARD in some soils. Preplant soil fumigation improves root system development, tree growth, and cropping in some orchard sites (Hoestra and Oostenbrink, 1962; Jaffee and Mali, 1979; Mai and Parker, 1970). We examined the effects on tree performance of preplant soil fumigation, a postplant nematicide treatment, and rootstock at the Univ. of Vermont Horticultural Research Center in 1983. Results for 1983–1985 were reported by Costante et al. (1987). We now present results for the final 4 years of the experiment (1986-1989). Trees were on a well-drained Adams loamy sand (pH 6.2) on a 20-year-old orchard site infested with P. penetrans and with a diagnosed replant” disease problem (Costante et al., 1987). Eighty ‘Rogers Red McIntosh’ trees each on semi-dwarfing MM.111, MM. 106, M.7a, or dwarfing M.26 rootstock were planted on 2 May 1984 at 2.4 x 5.5 m spacing, including appropriate buffer areas.

Managing potato cyst nematodes to minimize nematicide use1

Potato cyst nematodes (PCN), Globodera rostochiensis and G. pallida, are widespread in the ware potato‐growing areas of the UK. Traditionally they were controlled by rotation but more intensive production methods have increased the PCN threat, especially from G. pallida. G. rosrochiensis has become less important since cultivars fully resistant to it were introduced but, where both species are present in a mixture, the G. pallida portion comes to dominate. It is possible to control G. pallida as effectively as G. rostochiensis if cultivars partially resistant to G. pallida are grown with nematicide treatment. Where nematicide is not used, control of G. pallida is more variable. In some years, some cultivars achieve good control but the results are not consistent. In general, G. pallida has increased on untreated plots about 5‐fold in trials in the last 3 years.

Effect of crop rotation on Globodera rostochiensis and on potato yield1

A crop rotation field study was conducted in 1981–1989 to assess the effect of six crop rotation sequences on a soil population of potato cyst nematode (PCN), Globodera rostochiensis, and on potato yield. In the plots with potato monoculture, the tuber yield decreased from 35 to 4.6 t ha−1. All other cropping systems maintained the yield at the original or an even higher level. In monoculture, the population density of the nematode was raised during the first 3 years from 0.1 to 265 larvae g−1 soil, and the density fluctuated afterwards between 30 and 136 larvae g−1 soil. Three of the cropping systems, (1) susceptible potato once in 5 years, (2) susceptible potato once in 4 years, and (3) potato once in 3 years using resistant (H1) and susceptible cultivars alternately, decreased the nematode density under the economic threshold or even under the level of detection. The nematicide treatments (oxamyl) did not control nematode multiplication but prevented yield losses. No nematicide is currently registered nor needed for the control of PCN in Finland. The nematode can be controlled effectively with crop rotation, resistant cultivars and early harvesting.

Field trials using single potato plants as whole plots, with and without nematicide treatment, to assess tolerance of attack by Globodera rostochiensis

SummaryIt is important to assess the tolerance of new potato cultivars with partial resistance to potato cyst nematode attack. The experiments described here are intended to quantify tolerance adequately using a minimum of resources. When test plants were spaced widely in the field trials it was also possible to estimate their resistance levels but standard plant spacing allowed roots of neighbouring plants to encroach on a test plant's root space and to interfere with attempts to assay resistance. Standard plant spacing did, however, give more realistic yields per plant and competition from neighbouring plants was standardised by surrounding each test plant by four identical guard plants (cv. Désirée). Regressions of yield on severity of nematode attack were drawn when nematode infestation varied naturally across the trial site or when different levels of attack were created by applying nematicide at a range of dose rates. Cara was the most tolerant cultivar tested, with a complete spectrum of tolerance shown by other cultivars/clones. Some clones with a high degree of resistance were intolerant and it is precisely these that this type of test seeks to identify.

The impact of pests and diseases on the herbage yield of permanent grassland at eight sites in England and Wales

SUMMARYPlots at each of eight widespread permanent pasture sites below 300 m and representative of large areas of long established grassland in England and Wales, were treated with an insecticide plus molluscicide, a fungicide or nematicide treatment. Populations of various invertebrates and the occurrence of foliar fungal diseases were assessed.Leaf blotch (Drechslera) was the most common disease, but neither this nor other foliar fungal diseases were prevalent until late in the growing season. The fungicide treatment did not control diseases satisfactorily. The fungicide and nematicide treatment had little effect on total annual herbage yield. Leatherjackets, crambids, slugs and frit fly larvae were present, usually in low numbers, at most sites. The insecticide and molluscicide treatment increased yield by 11% on average across all sites and years. Losses caused by pests to UK grasslands were estimated to be over £500 million per year.

Effects of leaf‐matter incorporation on Aphelenchoides composticola (Nematoda), mycofloral composition, mushroom compost quality and yield of Agaricus bisporus

SummaryIncorporation of dried leaves of Azadirachta indica, Cannabis sativa, Eucalyptus tereticornis and Ricinus communis at 3 kg per 100 kg of dry wheat straw prior to composting had several effects. When compared with controls, treated composts exhibited a higher temperature during composting, a higher nitrogen content and a neutral pH. The treatments resulted in enhanced populations of thermophilic fungi and mesophilic antibiotic‐producing fungi, but reduced numbers of mesophilic competitor/pathogenic moulds. Populations of the mycophagous nematode, Aphelenchoides composticola were reduced below economic injury level in dried leaf treated composts.Compost obtained from C. sativa and R. communis treatments were more rapidly colonised by the mushroom mycelium (Agaricus bisporus) than that from any other treatment. When compared with compost treated with carbofuran R. communis, C. sativa and A. indica treatments significantly increased mushroom yield by 19.4, 8.1 and 6.5% and by 108.5, 88.7 and 85.9% when compared with the control. Yield from the E. tereticornis treatment was also higher than the control but lower than that of the nematicide treatment.

EFFECT OF ALDICARB, ALDOXYCARB AND OXAMYL ON POTATO TUBER YIELDS AND ROOT LESION NEMATODES

In a 3-yr field study at Upton, Prince Edward Island, aldicarb at 1.12 and 2.24 kg a.i. ha−1 and oxamyl at 2.24 kg a.i. ha−1 were applied in the furrow with seed potatoes. Nematicide treatments increased tuber yields of Superior by 15.5% (4.6 t ha−1) and yields of Russet Burbank by 9.3% (3.4 t ha−1). Shepody did not respond to nematicide treatments. The effect of aldicarb on average yields of all three cultivars did not differ from that of oxamyl, nor did yields at the higher rate of aldicarb differ from those at the lower rate. In a two-year field study at Harrington, Prince Edward Island, aldicarb and aldoxycarb applied at a rate of 2.24 kg a.i. ha−1 increased yields of Superior by similar amounts of about 40% (9.4 t ha−1). Oxamyl applied at the same rate in the second year had the same impact on yields as aldicarb or aldoxycarb. Nematicide treatments reduced the numbers of root lesion nematodes (primarily Pratylenchus penetrans) in roots and soil at Upton. Both rates of aldicarb had a similar impact, but oxamyl was less effective than the aldicarb treatments in reducing nematode numbers in roots. At Harrington, aldicarb controlled nematode populations more efficiently than aldoxycarb in soil in the first year and in roots in the second year. Aldoxycarb and oxamyl reduced nematode populations to a similar degree.Key words: Aldicarb, aldoxycarb, oxamyl, Pratylenchus penetrans, Solanum tuberosum

Organic Amendments for Control of Root-Knot Nematode (Meloidogyne Incognita) on Ginger.

Poultry manure and sawdust (24, 36 or 48 tlha) were incorporated into soil with urea (0–1800 kg nitrogenlha) and their effects on yield of ginger and populations of Meloidogyne incognita were compared with those of nematicide programmes involving ethylene dibromide andlor fenamiphos. The pre-plant nematicide treatments proved inadequate but improved nematode control was achieved when these treatments were followed by postplant applications of fenamiphos. Total yields in soil amended with poultry manure or sawdust plus urea were greater than in non-amended soil and equal to or greater than those in the best nematicide treatments. The yield increase for poultry manure appeared to be due in part to its beneficial effects on soil fertility. Both amendments provided good control of root-knot nematodes, with significantly fewer rhizomes being discarded at late harvest from the amendment treatments than from the untreated and some nematicide-treated plots. Addition of the highest rates of urea to soil produced ammonium-nitrogen concentrations of more than 1000 μ/g soil, but no measurable effect on root-knot nematode populations or the degree of nematode damage.

Field investigation of the responses to nematicide treatment of three winter oilseed rape cultivars infested by Heterodera cruciferae

Three winter oilseed rape cultivars (Bienvenu, Jet Neuf, Mikado) grown in a field heavily infested with Heterodera cruciferae showed no evidence of cultivar resistance to the nematode. Aldicarb applied at drilling time significantly improved growth and yield of all cultivars. Plant population was not affected by nematicide treatment. Yield was improved by an average of 0 · 66 t/ha but there was no evidence of a significant difference in yield response between the cultivars. Aldicarb did not affect invasion or reproduction of H. cruciferae; the post-cropping nematode population density was higher than the precropping density for all cultivars whether or not a nematicide was applied.

Effects of Monocropping Resistant and Suspectible Soybean Cultivars on Cyst Nematode Infested Soil1

Studies of soybean [Glycine max (L.) Merr.] cultivar sequence and use of nematicides were conducted on a soil uniformly infested with the soybean cyst nematode (SCN), Heterodera glycines Ichinohe. Assumption that new races of SCN would develop rapidly if only SCN resistant cultivars were grown had led to specific recommendations that SCN resistant cultivars not be grown > 2 yr without rotating with a SCN susceptible cultivar or a nonhost crop. No field data were available to support the recommendation. This study was initiated in 1976 to more critically evaluate the effects of SCN on soybean productivity in a long‐term monocropping program. Resistant to SCN race 3, ‘Centennial’, and one that is susceptible, ‘Tracy’, were grown continuously with and without a nematicide. The nematicide treatment was dropped after 6 yr. The two cultivars were also grown in a sequence of 2 yr of Centennial and 1 yr of Tracy and in a blend of 80% Centennial with 20% Tracy. A breeding line resistant to SCN races 3 and 4 constitutedhn additional treatment. Sorghum [Sorghum bicolor (L.) Moench.] replaced the nematicide treatment in the seventh or seventh and eighth years to be followed by Tracy. Nematicide treatment did not enhance seed yield for either the susceptible or the resistant cultivar. No treatment was superior to growing the SCN race 3 resistant cultivar Centennial continuously over the 10‐yr period. No advantages were determined for including a SCN susceptible cultivar in the program. Beginning with the third year of this study and seventh year of continuous soybean production, the SCN population appears to have stabilized at a low level.

Effects of Apple Rootstocks and Nematicides on Pratylenchus penetrans Populations and Apple Tree Growth

Abstract ‘Rogers Red McIntosh’ (Malus domestica Borkh.) on Mailing Merton (MM)111, MM 106, Mailing (M) 26 and M 7a were planted within an old apple orchard site. The trees were trickle-irrigated and the sandy soil was treated with the nematicides Telone (C-17), Vorlex, or Nemacur 3. In 1984, data were collected from trees excavated at 50, 100, and 156 days after planting and from permanent trees in 1985 from plots treated with nematicides prior to planting. The numbers of Pratylenchus penetrans [(Cobb) Filipjev & Schuurmans-Stekhoven] in soil and rootstocks from nematicide treatments and controls were well below reported damage levels and not considered a problem on this test site. M 111 and MM 106 roots and ‘McIntosh’ scion growth were superior to M 26 and M 7a counterparts regardless of soil treatment in 1984, while only the scions on MM 111 were larger than those on M 26 in 1985. ‘McIntosh’ scions grew 36% larger on Telone C-17-treated soil and 19% larger on Vorlex-treated soil than on untreated soil. Leaf and soil analyses showed no interaction with rootstocks and minor differences between soil treatments in both years. A soil replant bioassay revealed disease factor(s), including P. penetrans, present in untreated soil.

Ryegrass establishment and yield in relation to pesticide treatment, irrigation and fertiliser level

SUMMARYThe effects of irrigation, four fertiliser rates, fungicide, insecticide + molluscicide, and nematicide treatments were tested on an Italian ryegrass sward sown in May 1983, in a multi‐factorial experiment that allowed treatment interactions to be examined.Pests and fungal diseases were monitored over a 2‐yr period. No recognised grassland insect pests or slugs were found in the seedbed but there were an estimated 17 300 plant parasitic nematodes/litre soil. Other, non‐pest invertebrate populations, e.g. earthworms, were not assessed.In the first year yields were increased most by irrigation. There were also large yield responses to fertiliser over the range 50–900 kg N/ha/yr. Responses to pesticide application were relatively small. However, there were significant yield responses in the first year to nematicide and to insecticide + molluscicide treatments.Yields in the second year were affected more by increased fertiliser use than by irrigation; increases after pesticide use were similar to the previous year, and there was also a small but significant yield gain over untreated plots at the second harvest from those treated with fungicide.Interactions between main factors occurred in both years, affecting yields and nematode abundance. Nematode numbers were decreased in both years where the larger, compared to the smaller fertiliser applications had been made. In the first year these differences were only apparent on irrigated plots.It was concluded that, in this trial, irrigation had the greatest effect on yields of spring‐sown ryegrass during its establishment year but that increasing fertiliser rates had a greater effect the year after; that fungi had had little effect on ryegrass yields, and that nematodes were more important pests than insects during establishment but insects were more important subsequently.

Trophic Interactions and Nitrogen Cycling in a Semi-Arid Grassland Soil. II. System Responses to Removal of Different Groups of Soil Microbes or Fauna

(1) Perturbations were performed on organisms in a below-ground trophic food web in a semi-arid grassland, using five separate biocide treatments to observe changes in trophic structures, interactions, and nutrient cycling. Changes in N mineralization and trophic interactions as predicted on the basis of simple predator-prey microcosm studies were observed following removal of particular groups. (2) Five biocides: streptomycin (bactericide), captan and PCNB (fungicides), carbofuran (insecticide-nematicide), and cygon (acaricide) were applied in situ to soil in cylinders containing predominantly blue grama grass. The response of microbes, fungal grazers, soil inorganic N and plants were followed monthly between April and October 1982. (3) Grazing of bacteria or fungi by predators resulted in one or more of the following occurrences: (i) increased soil inorganic N, decreased predator populations following reduction of prey or increased plant growth after reduction of nematodes; (ii) reduction of one group of decomposers, e.g. bacteria, allowed a second decomposer group, e.g., fungi, to increase in numbers; (iii) compensatory responses of microbial feeders, e.g. decreases in bacterial feeders (protozoa and bacterivorous nematodes) were followed by compensatory increases in fungal feeders, which increased following the increase in their fungal food supply. (4) Continuing changes in nitrogen cycling were not observed, presumably because the function of the reduced group was compensated by increased numbers of the second group performing a similar function. Nematode-VAM interactions must be considered in food web and nutrient flows, as the percentage of VAM colonization of plant roots increased markedly when nematode populations were decreased by nematicide treatment. Production of predator biomass was as important as microbial and plant production in determining nutrient flow in this system.

Yield losses caused by potato cyst nematodes: a review of the current position in Britain and prospects for improvements

SUMMARYStudies of the yield losses caused by potato cyst nematodes (PCN) in Britain are reviewed.The main conclusions either drawn from or supported by the literature, are:‐ 1) The models/equations used to relate yield losses to pre‐planting densities of PCN are not entirely satisfactory. 2) There is considerable variation between sites in the damage caused by PCN and hence the yield response to nematicide treatment cannot be reliably predicted. 3) Oximecarbamate nematicides, if well applied and if other damaging pests are absent, will prevent most of the loss at infested sites but do not increase yields at most uninfested sites. 4) PCN decreases yields by reducing the effectiveness of the root system, and hence leaf area duration and the amount of light intercepted by the crop canopy: in some circumstances PCN may also decrease the efficiency of assimilation. 5) Several factors interact either to increase or to decrease the damage caused by PCN; some of the more important are soil type, interactions with micro‐organisms, differences in husbandry, differences between cultivars in their tolerance of damage, the weather and differences in yield potential between sites. 6) Both the yield losses caused by Globodera pallida and the amounts of nematicide used may be decreased by planting tolerant and partially resistant cultivars.New results are used to show that yield losses may be decreased by applying extra fertiliser and that low rates of nematicides may be adequate to prevent damage to tolerant cultivars. Further research may lead to an improved basis for advice relating to the control of PCN and the damage it causes.

Effect of fertilizer and nematicide treatments on crops grown for biomass

Successful production of biomass for energy requires selection of species with high annual yields and development of proper management conditions. Pennisetum purpureum, Erianthus arundinaceum, Sorghum bicolar, and Tripsacum dactyloides were grown as single biomass crops and Brassica campestris, Sorghum bicolor were grown in sequence under one nematicide and two fertilization treatments. The experiment was conducted over a three year period. P. purpureum (52·2 Mg ha −1) and Erianthus (46·4 Mg ha −1) produced highest dry biomass yield when recommended fertilizer rate for forage production was applied and the plants were cut once each year. Harvesting P. purpureum twice each year reduced yields 65% compared with the single cut. Decreasing fertilizer by one-half lowered yield 14–26% for P. purpureum and sorghums; 49% for T. dactyloides (zero fertilizer applied), whereas Erianthus increased from 46·4 to 54·0 Mg ha −1 with the lower fertility. The application of 6·7 kg ha −1 active nematicide on the soil surface in late March of each year did not control nematodes nor affect yields. Biomass yields from P. purpureum and Erianthus when grown on flatwood soils in peninsular Florida at the normal fertilizer rate and harvested once per year were higher than yields at reduced fertilizer treatments. Additional research is needed to determine optimum fertilizer levels for each grass grown under specific soil conditions.

Integrated control of the root-knot nematode, Meloidogyne incognita, on black-pepper plantations in the amazonian region

In the Amazonian region, so-called foot-rot disease, caused by a fungus Nectria, occurs widely on black-peppers, Piper nigrum L., the roots of which are also heavily infested by the root-knot nematode, Meloidogyne incognita. Factorial experiments were conducted in this region during 1976–1978 to attempt to find out the effect of nematicide treatment, mulching with Imperata cylindrica, and non-host cover plantings, on the growth of black-peppers as well as on nematode population levels. Temic or Furadan treatment resulted in better plant growth and a reduced nematode population in the first year. Mulching resulted in exceedingly high plant growth, even though higher nematode populations were also observed. Under mulching conditions, soil temperatures at 5-cm depth seldom rose beyond 30°C throughout the year. Cover plantings of non-hosts, which had been selected by earlier inoculation tests, indicated remarkable retardation of plant growth of black-peppers, evidently due to the competition, and this also reduced the nematode population. Macroptilium atropurpureum (siratro) gave the smallest growth retardation of black-peppers. From these results, a combination of three procedures, i.e. Temic or Furadan treatment, mulching with grass straw, and cover-planting of non-hosts such as siratro, is recommended on black-pepper plantations for better plant growth and eventually better yield of black-peppers in the fields infested by root-knot nematodes.

Efeito do controle de nematóides na qualidade da fibra do algodoeiro

Avaliou-se o efeito do tratamento com torta de mamona e com nematicidas sistêmicos (aldicarb, carbofurã, oxamil e sulfona de aldicarb), na qualidade das fibras do algodoeiro (Gossypium hirsutum cv. IAC 17) cultivado em área infestada por Meloidogyne incognita, Pratylenchus brachyurus, Helicotylenchus dihysteroides e Xiphinema sp., no nunicípio de Paranapanema, no Estado de São Paulo. As características afetadas foram: o comprimento das fibras, no qual só o carbofurã produziu aumento significativo; a resistência das fibras, que aumentou com os tratamentos torta de mamona e aldicarb; e a maturidade das fibras, onde, com exceção do oxamil, todos os tratamentos foram superiores à testemunha. As características de uniformidade e índice de finura das fibras não diferiram da testemunha em nenhum dos tratamentos.

The relationship of potato yield with and without nematicide to density of potato cyst nematodes, lobodera rostochiensis and G. pallida

SUMMARYTrials relating response to nematicide to potato cyst nematode density were conducted initially in the West Midlands and later in other Regions. Thirteen trials, only three of which were within the intensive potato growing areas, conformed to a general pattern with yield losses being largely recouped by nematicide treatment. Five trials, four within the intensive areas, gave no correlation between potato yield and nematode density and an unpredictable response to nematicide. The control of the nematode appeared to be poorer in the latter trials but other factors affecting yield and nematode multiplication may have been involved. It is speculated the main factor might be interaction with fungal organisms e.g. Rhizoctonia or Verticillium.Evidence is presented to show that on several trials the nematicide has an effect other than by controlling potato cyst nematodes.Yield losses caused by potato cyst nematodes are more variable than previous work indicated, probably due to varietal, seasonal or environmental influences.