Effects of insecticides applied to control cucumber beetles (Coleoptera: Chrysomelidae) on watermelon yields

Foliar insecticides applied to control the striped and spotted cucumber beetles, Acalymma vittatum (Fab.) and Diabrotica undecimpunctata howardi Barber, on watermelon, Citrullus lanatus, were of little or no value in three studies conducted in two locations over 2 years. However, an at-planting application of the systemic, soil insecticide carbofuran resulted in higher early yields, although the differences were not statistically significant in small plots. In 1991, large plots comparing carbofuran-treated watermelons with untreated watermelons in two commercial fields showed large and statistically significant increases in melon yield when carbofuran was applied, especially in early yield. Studies in 1992 and 1993 showed that the application of carbofuran at planting stimulated root and shoot growth after transplating and increased yields when compared with untreated plots, plots treated with methyl bromide, or another soil insecticide, terbufos. These studies suggest that carbofuran may be acting as a growth stimulant, as well as an insecticide.     

Insecticidal control of cereal aphids and its impact on the epidemiology of the barley yellow dwarf luteoviruses

Imidacloprid is a seed-applied nitroguanidine insecticide that has both contact and long-lasting systemic properties. Its direct effects on cereal aphid populations and indirect effects on barley yellow dwarf luteovirus (BYDV) incidence were examined in laboratory and field studies. Adult longevity and fecundity of three aphid species caged on various aged, imidacloprid-treated oat or wheat plants was reduced, although the quantitative efficacy of the compound differed among aphid species. The transmission efficiency of BYDV by aphids to imidacloprid-treated plants was lower, relative to nontreated plants, when plants were 10 days old, but similar to nontreated when plants were 24 days old. In three years of field trials using winter wheat and two years using spring oat, aphid populations were reduced significantly in imidacloprid-treated plots relative to nontreated plots. Although the number of alighting alate aphids did not differ significantly between imidacloprid-treated or nontreated plots, the number of apterous aphids remained significantly lower in the treated plots for the majority of the growing season. BYDV epidemics did not develop in spring oat in either of the two years. BYDV epidemics did develop in the fall in the emerging winter wheat crop. Rhopalosiphum maidis was the predominant aphid migrating into the 1991–1992 crop. The incidence of the BYDV-RMV serotype was three times higher in nontreated plots than in imidacloprid-treated plots. In the 1992–1993 and 1994–1995 seasons, R. maidis and R. padi were the predominant aphids migrating into the crop, although R. padi was the predominant colonizing aphid. The incidence of BYDV-RMV was similar in imidacloprid treated and nontreated plots in 1992–1993, but the incidence of the BYDV-PAV serotype was significantly less in the treated plots. In 1994–1995, the incidence of both BYDV-PAV and BYDV-RMV was higher in the nontreated plots than in the imidacloprid-treated plots. Imidacloprid offers several advantages both in terms of its long-lasting systemic activity and its mode of applicaiton. As a seed treatment, the amount of material applied is minimized, there is little waste and the environmental impacts are reduced. The effectiveness of the compound at reducing the fecundity or reproductive rate of several aphid species may be advantageous in controlling secondary spread of viruses. However, the contact properties of the compound, important in repelling aphids or preventing phloem feeding, may be short-lived, thus reducing its effectiveness in preventing primary spread of the virus into the crop, especially under high aphid and inoculum pressure.     

Field tests of Trichoderma harzianum Rifai aggr. as a biocontrol agent of seedling disease in several crops and Rhizoctonia root rot of sugar beet

In field studies, mean stands of crops of snapbean, field corn, pea, soybean, and squash in New York were somewhat greater from seeds treated with conidia of Trichoderma harzianum applied in a Methocel slurry than from non-treated controls; however, stands were generally poorer than those from captan-treated seed. The biocontrol agent and captan had little effect on kidney bean and sweet corn since these crops are only slightly susceptible to seedling disease caused by Pythium spp. which were present in the field. In Colorado fields also infested with Pythium spp., stands of sugar beet from T. harzianum-treated seed (Pelgel slurry) tended to be greater than those from non-treated seed and equal to those from maneb-treated seed, but differences were not significant. In Colorado, Rhizoctonia solani, cause of root rot, was also present in the soil. A combined analysis of variance of treatments across 2 years showed that a preplanting-incorporated in-row application of T. harzianum in a wheat-bran carrier or a maneb seed treatment slightly, but significantly, reduced the severity of Rhizoctonia root rot in sugar beet as compared with the non-treated control. Seed treatments with T. harzianum had little or no effect. In plots where the agent was applied to the soil, numbers of Trichoderma propagules increased 600-fold by harvest; where maneb seed treatment was used, they increased only fivefold. Densities of the agent remained the same or decreased in plots where Trichoderma was used as a seed treatment.     

The effect of fungicides on sugar beet infected with beet mild yellowing virus

Studies were made in 1989, 1990 and 1991 to establish whether carbendazim (MBC) had a direct therapeutic effect on sugar beet plants infected with beet mild yellowing virus (BMW), resulting in detectable yield benefits. In a field trial in 1989 virus-infected plots treated with carbendazim gave a significantly higher yield, of 0.66 t sugar/ha, than virus-infected plots sprayed with sulphur to control powdery mildew. This response to carbendazim in virus-inoculated plots was not repeated in subsequent trials in 1990 and 1991, and a glasshouse study showed no apparent effect on virus concentration within inoculated plants. Neither was any effect of carbendazim on symptom development observed in any of the trials or glasshouse experiments.     

Control of maize pests with imidacloprid seed dressing treatment in Catalonia (NE Iberian Peninsula) under traditional crop conditions

The effects of treating maize seed with imidacloprid to prevent damage by soil pests, aphids, leafhoppers and the first generation of corn borers was evaluated in the field by comparing treated with untreated commercial plots in a 5-year study in Catalonia (NE Iberian Peninsula). The treatment reduced the incidence of cutworms (Agrotis segetum), wireworms (Agriotes lineatus), the first generation of the corn borer Sesamia nonagrioides and leafhoppers (Zyginidia scutellaris). However, treated plots were attacked significantly more by Ostrinia nubilalis. The treatment was effective in reducing aphid densities from maize emergence to mid June. What happened later depended on the relative abundance of aphid species. Rhopalosiphum padi seems to be more sensitive than Metopolophium dirhodum whose population can be enhanced after flowering in plots treated with imidacloprid. The treatment did not avoid aphid alate colonisation and MDMV infection was not prevented. The greater damage on untreated plants caused by wireworms, cutworms and the first generation of S. nonagrioides, and the densities achieved by aphids, was insufficient to produce yield differences between treatments, and only leafhopper damage led to economic damage. Imidacloprid favours the attack of the European corn borer, thus masking the potential increase in yield.     

Plant protection in spring cereal production with reduced tillage. II. Pests and beneficial insects

In five field experiments run for four years the infestation of pests and the activity of carabids and staphylinids were compared in autumn ploughed and reduced tillage (no-tillage or spring harrowing) plots. Differences were generally most evident in experiments with no-tillage. Weed cover was denser in reduced tillage, and could explain much of the differences. The agromyzid Chromatomyia fuscula was most common in autumn ploughed plots, probably due to healthier plants. Thrips numbers were correlated with grain quality in no-tillage plots. Field slugs were most common in reduced tillage, and were positively correlated with weed cover. Generally, more carabids and staphylinids were caught in reduced tillage. This was especially true for Amara-species and Loricera pilicornis, Philonthus cognatus and Tachinus signatus, which also were positively correlated with weed cover. Aloconota gregaria, Bembidion quadrimaculatum, B. lampros, Harpalus rufipes and Trechus quadristriatus were more common in autumn ploughed plots, several of them preferring open soil.     

Integration of Pseudomonas fluorescens and acibenzolar-S-methyl to control bacterial spot disease of tomato

Xanthomonas axonopodis pv. vesicatoria was isolated from infected tomato seedlings grown in an open field in Egypt. All the tested isolates infected tomato plants but with different degrees of disease severity. In an attempt to manage this disease, tomato seeds and/or seedlings were treated with an antagonistic local isolate of Pseudomonas fluorescens as a suspension or its formulation or acibenzolar-S-methyl (BTH). When the above three treatments were applied to tomato seeds under laboratory conditions, they improved seed germination and seedlings vigour relative to control seeds treated with sterile distilled water and pathogen but P. fluorescens culture was the most effective. Under greenhouse and field conditions, combinations of the above treatments were used. All treatments significantly reduced disease severity of bacterial spot in tomato relative to the infected control. The biggest disease reduction compared to seedlings inoculated with the pathogen alone resulted from a foliar application of P. fluorescens. Combined application of P. fluorescens or its formulation with BTH reduced the pathogen population and increased seedling biomass and tomato yield relative to control seedlings.     

Effect of host plant resistance and insecticide on brown planthopper Nilaparvata lugens (Stål) and predator population development in the Mekong Delta, Vietnam

Crop yield and populations of brown planthopper Nilaparvata lugens (Stål), whitebacked planthopper Sogatella furcifera (Horvath) (Homoptera: Delphacidae), green leafhopper Nephotettix spp. (Homoptera: Cicadellidae), and hemipteran and spider predators were monitored on rice varieties susceptible, moderately resistant, and highly resistant to N. lugens, under insecticide-treated and insecticide-free conditions. Nilaparvata lugens outbreaks and hopperburned plants were observed only in plots of the insecticide-treated susceptible varieties. In insecticide-free plots, the yield of the susceptible variety was lower than those of resistant varieties in only one of four seasons. In plots of a moderately resistant and a highly resistant variety, populations of N. lugens, S. furcifera, Nephotettix spp., and predators were generally similar, and yields did not differ, under both insecticide-treated and insecticide-free conditions. In insecticide-free plots, predator-N. lugens ratios were generally higher on resistant varieties than susceptible varieties. Two conclusions can'be drawn from our results relevant to the question of what levels of N. lugens host plant resistance are appropriate for farmers who do not overuse insecticides. First, susceptible varieties will not necessarily be damaged by N. lugens, even when N. lugens outbreaks occur in adjacent plots. Second, moderate and high levels of N. lugens resistance do not appear to be incompatible with biological control of N. lugens or other homopteran pests.     

Efficacy of metam sodium for controllingVerticillium dahliae prior to potato production in sandy soils

The efficacy of metam sodium (MS) for controlling Verticillium wilt of potato was evaluated in two field experiments conducted in a sandy soil, heavily infested withVerticillium dahliae, and previously treated with MS. Compared to control plots where AUDPC value was 3141 (in 1999) and stem infection was 71.2% (in 2000), in plots treated with 600 L MS/ha AUDPC values were reduced by 57% to 80%, and stem infection was reduced by 49–54%. The incidence of infected dry stems, evaluated at the end of each season, was significantly reduced by all MS treatments, especially by 900 L/ha applied to a 60-cm depth (1999). Disease incidence in daughter tubers was also significantly reduced by all MS treatments. Yields obtained with 600 L/ha MS applied to a 30-cm depth were 32% and 21% higher than in the control in 1999 and 2000, respectively. In plots treated with 600 L/ha MS applied to a 60-cm depth yields were 17% and 28% higher than in the control in 1999 and 2000, respectively. With 900 L/ha MS applied to a 60-cm depth, yield was 21% higher than in the control in 1999. The yield of the low MS dose (300 L/ha), applied only in 2000, was not significantly different from the control. The differences in yield were due to the greater percentage of tubers larger than 45 mm. Yield reduction was highly correlated with disease severity expressed as AUDPC (in 1999 experiment). The net income in the 600 L MS/ha treatments was higher than in the control in both experiments. No indication of enhanced biodegradation was observed in the present study.     

Effect of fertilizer,fumigants, and fungicides on leafroll-net necrosis in Russet Burbank potatoes

A total of 112 combinations of 13 fumigants, fertilizers, and a fungicide was tested in replicated plots in eastern Washington in 1963 and 1964 to determine their effects on the net necrosis produced in Russet Burbank potatoes by the leafroll virus. Plots treated with Telone^® (dichloropropenes) or Telone+chloropicrin had significantly fewer tubers discolored with leafroll net necrosis than untreated plots; plots treated with lower rates of various chlorinated propenes and propanes or ethylene dibromide had fewer discolored tubers than plots treated with higher rates of these chemicals; and plots treated with higher rates of various combinations of dichloropropenes with methyl isothiocyanate or 3-bromo-1-propyne had fewer discolored tubers than plots treated with lower rates of these chemicals. An interaction took place between the chemicals and the leafroll virus that either increased or decreased the amount of net necrosis in the tubers. Other types of internal discoloration (OID) in the tubers were significantly increased by Telone treatments in some tests. Telone treatments showed no effects on OID in other tests compared to untreated tubers. Also, nitrogen, at 100 lb/acre and over, significantly increased the other types of discoloration over no nitrogen, but potassium at 0 to 150 lb/acre and pentachloronitrobenzene (PCNB) at 0 to 30 gal/acre showed no significant effect.     

Amelioration of dense sodic subsoil using organic amendments increases wheat yield more than using gypsum in a high rainfall zone of southern Australia

Subsoil constraints are major limiting factors in crop production in many soils of southern Australia. A field study examined effects of deep incorporation of organic and inorganic amendments in 30–40 cm on soil properties, plant growth and grain yield of wheat (Triticum aestivum var. Ambrook) on a Sodosol with dense sodic subsoil with or without lucerne history in a high rainfall region (long-term average annual rainfall 576 mm) of Victoria. Amendments were applied at a rate of 10–20 t ha⁻¹. Deep ripping alone and deep ripping with gypsum did not significantly affect grain yields. In comparison, application of organic materials doubled biomass production and increased grain yield by 1.7 times. Organic amendment-treated plots produced 60% more grains per area than the untreated control. The crop extracted over 50 mm extra water from below 40 cm soil in organic amendment-treated plots than the untreated control. Nitrogen uptake was almost doubled (403 kg ha⁻¹) in the organic amendment-treated plots than the untreated control (165 kg ha⁻¹). The improved yield with amendments was related to an increase in plant available water in the hostile subsoil, and prolonged greenness of leaves and supply of nitrogen and other nutrients.     

Comparison of molluscicides based on metaldehyde, methiocarb or aluminium sulphate

In a field trial in November 1984, six proprietary molluscicides reduced slug damage to Chinese cabbage seedlings. None gave complete protection. Plant damage was less after treatment with a paste formulation of metaldehyde than after application of metaldehyde in loose bran, but no other significant differences between chemicals were observed. Effects of molluscicides on slug numbers and activity from 2 to 14 days after application, as determined by traps baited with loose bran, were more complex. Neither metaldehyde nor methiocarb pellets significantly decreased the numbers of Deroceras spp., Arion ater, A. hortensis agg. and Milex sowerbyi that were trapped. Numbers of D. reticulatum trapped in grass and M. sowerbyi in all traps were significantly greater on plots treated with metaldehyde than on untreated plots. Methiocarb pellets significantly reduced numbers of A. fasciatus agg., A. subfuscus and M. budapestensis. The times taken to apply different treatments in the field were noted. In the laboratory, some Deroceras reticulatum recovered from all molluscicide treatments used at recommended rates. Only methiocarb killed significant numbers in the laboratory. Even apparently healthy slugs consumed less food for c. 6 days after exposure to metaldehyde or methiocarb. The relevance of these observations to prevention of slug damage is discussed.     

Yield losses in soybeans from frogeye leaf spot caused by Cercospora sojina

Three soybean [Glycine max (L.) Merr.]cultivars (Samsoy 1, TGx 1025-12E and TGx 996-26E) were evaluated for yield losses resulting from frogeye leaf spot caused by Cercospora sojina Hara. Replicated field plots were established at two locations in Nigeria that have a high natural infestation of C. sojina. The cultivars were either not sprayed, sprayed once or sprayed twice during the growing season with the fungicide benomyl. Disease spread early in the season was from border rows of a susceptible soybean cultivar into the plots. Mean disease severity (DS) for unsprayed cultivars ranged from 0.6 to 4.5 on a scale of 0–5. Plots receiving two sprays had lower DS values, ranging from 0.5 to 2.4. Differences between unsprayed and double-sprayed plots for yield and 300-seed weight ranged from 2.5 to 58.8 and 0.6 to 28.6%, respectively. Seed weight was negatively correlated with DS.     

Effect of watered-in demethylation-inhibitor fungicide and paclobutrazol applications on foliar disease severity and turfgrass quality of creeping bentgrass putting greens

Preventive, watered-in applications of DMI fungicides provide control of several soilborne turfgrass diseases on golf putting greens. The objectives of this two-year field study were to determine the impact of these applications on foliar diseases, and evaluate the impact of application timing of paclobutrazol, a plant growth regulator, on disease severity and turfgrass quality. Triadimefon (1.58 kg a.i. ha⁻¹), tebuconazole (0.82 kg a.i. ha⁻¹), metconazole (0.43 kg a.i. ha⁻¹), and triticonazole (0.64 kg a.i. ha⁻¹), were applied twice in late April and May and immediately watered in to the soil profile with 5 mm of post application irrigation. Paclobutrazol (0.28 kg a.i. ha⁻¹) was applied alone, in a tank-mix with the fungicide application, 7 days or 14 days after the fungicide application. Overall dollar spot severity, assessed as area under the disease progress curve (AUDPC), was significantly lower in fungicide treated plots than non-treated plots in both trial years. The date of threshold symptom observation (≥5 infection centers per plot), however, was not different between fungicide treated and non-treated plots in 2011. Triadimefon treated plots had lower AUDPC values than other fungicide treatments. Brown patch severity was not significantly different among treatments. Paclobutrazol applied alone did not reduce dollar spot or brown patch severity, however, paclobutrazol + fungicide treatments resulted in lower dollar spot severity than plots treated with fungicide alone. Short-lived phytotoxicity (bronze discoloration) was observed in plots treated with triadimefon or paclobutrazol + fungicide. Spring preventive fungicide applications targeted at soilborne disease control also provided residual control of dollar spot in this study.     

Effects of fungicides on eyespot in five successive crops of winter wheat in plots with different initial or fungicide-selected populations of Pseudocercosporella herpotrichoides

The effects on eyespot of carbendazim, prochloraz or a mixture of carbendazim and prochloraz, applied twice yearly and to the same plots in each year, were studied in five successive crops of winter wheat. Some plots were uninoculated (with a background population of the eyespot fungus, Pseudocercosporella herpotrichoides, which was initially mainly MBC-sensitive W-type), whereas others were inoculated artificially in the first autumn of the experiment (1984) with mainly MBC-sensitive W-type, MBC-resistant W-type, MBC-sensitive R-type or MBC-resistant R-type fungus. Samples were taken in April (1985–1987) and July (1985–1989). When all inoculation treatments are considered together, carbendazim was ineffective at all sampling times after April 1985 because of its rapid selection for MBC-resistance, and increased eyespot incidence and severity in some samples. Prochloraz applied alone decreased eyespot incidence and severity at all sample times except July 1988. Where applied with carbendazim, prochloraz always decreased eyespot incidence and severity, sometimes more so than when applied alone. The control of eyespot by the fungicides was influenced by the initial populations in the first two seasons only. Carbendazim decreased eyespot incidence in 1985 only where no artificial inoculum was added (both samples) and where mainly MBC-sensitive R-type inoculum was added (April 1985). Prochloraz applied alone was ineffective in July 1985 where mainly MBC-sensitive R-type fungus was added, and, applied with carbendazim, was ineffective in July 1986 where mainly MBC-resistant fungus was added. Subsequently, the populations were unrelated to the initial populations and were mainly a result of selection by fungicides where these were applied. Although selecting for the R-type fungus and, where no carbendazim was applied, for MBC-sensitivity, prochloraz remained generally effective after repeated applications over five seasons.     

Effects of fungicides used to control Rhynchosporium secalis where benzimidazole resistance is present

The effects of fungicides used to control Rhynchosporium secalis in winter barley were investigated in five field trials in Co. Down, Northern Ireland. Benzimidazole resistance was present in the R. secalis population of each site. Fungicide performance was evaluated in terms of disease control, maintenance of green leaf area, grain yield and grain quality. Samples of R. secalis isolates taken before and after treatment in each field were assessed for sensitivity to carbendazim in the laboratory. Carbendazim contributed little to disease control, the maintenance of green leaf area, grain yield or grain quality. Carbendazim was associated with a significant increase in disease severity in some plots. Treatments containing carbendazim, either alone or in mixture, caused an increase in the proportion of carbendazim-resistant isolates within R. secalis populations. Propiconazole-containing treatments performed well in terms of disease control, maintenance of green leaf area and grain quality. They caused no change in carbendazim resistance frequency.     

Reflective mulches for management of aphids and aphid-borne virus diseases in late-season cantaloupe (Cucumis melo L. var. cantalupensis)

A complex of aphids and several mosaic virus diseases can cause major losses in cucurbitaceous crops grown in the inland valleys of California. Three field experiments were conducted to test and compare the effectiveness of reflective polyethylene and biodegradable, synthetic latex spray mulches for management of aphids and aphid-borne virus diseases of late-season cantaloupe (Cucumis melo L. var. cantalupensis cv. Primo) in the San Joaquin Valley. Beneficial responses were obtained from the reflective mulches, under conditions of high aphid populations and virus inoculum potential, during each of the experiments. Aphid numbers on leaves of plants growing over mulches were consistently lower than on those growing over bare soil. Onset of symptoms of cucumber mosaic cucumovirus, and watermelon mosaic and zucchini yellow mosaic potyviruses, were delayed 3–6 weeks in plants growing over the mulches, which was critical for initiation of normal flowering and fruiting. High virus disease incidence (100% incidence of foliar symptoms) reduced cumulative, marketable melon yields (number of fruit, fresh weight, and size) in the control plots to near zero in two of the three experiments. In each of the experiments, polyethylene or spray mulch treatments which completely covered each planting bed provided at least 9.5- and 2.5-fold increases in marketable yield, respectively. In the first two experiments, reflective mulches would have provided the difference between salable crops and total crop loss. Partial bed coverage with spray mulch, and alternate row applications of polyethylene film mulches, were less effective than complete coverage of every planted row.     

The impact of toxaphene applied as a post-emergence herbicide for control of sicklepod, Cassia obtusifolia L., on arthropods associated with soybean

The impact on arthropod populations of toxaphene (camphechlor) used as a herbicide was compared with cultivation and pre-emergence herbicide usage for control of sicklepod, Cassia obtusifolia L., in soybean. Soybean yields and weed control were also evaluated. Pest resurgence due to toxaphene was found to be limited, but significantly more soybean plants had main stems girdled due to the threecornered alfalfa hopper, Spissistilus festinus (Say), than those plants where toxaphene had not been applied. Both toxaphene usage and cultivation reduced early season predator abundance significantly compared with soybean where weeds were not controlled. However, the greater abundance of predators in soybeans with weeds appeared to be attributable to the increase in habitat diversity provided by the weeds and soybeans and not to a reduction in predator numbers caused by toxaphene in the treated plots. Neither soybean yields, nor the degree of sicklepod control, differed significantly between toxaphene usage and cultivation. Permethrin usage significantly reduced both pest and predator abundance in soybean.     

Application of an emulsifiable mixture of 1,3-dichloropropene and chloropicrin against root knot nematodes and soilborne fungi for greenhouse tomatoes in Italy

A mixture of 1,3-dicloropropene 60.5% w/w and chloropicrin 33.3% w/w (Telone C35 EC) may be registered in Italy for soil drip fumigation. Five experiments on greenhouse tomatoes in Northern, Central and Southern Italy compared the effectiveness of this mixture in comparison with methyl bromide to find the optimum application rate in soils infested by Fusarium oxysporum f.sp. lycopersici, F. oxysporum f.sp. radicis lycopersici, Sclerotium rolfsii, Meloidogyne javanica and M. incognita. Its efficacy against F. oxysporum f.sp. radicis lycopersici and M. incognita was confirmed when applied to soils at 100, 200, 300 and 400 l ha⁻¹ (132.4, 268.4, 402.6 and 536.8 kg ha⁻¹) under gas-tight films with 15–45 mm of application water (900–1200 mg Telone C35 EC l⁻¹). In sandy soils, with slight F. radicis lycopersici infections and with heavy nematode (M. incognita) attacks, the mixture, drip applied at 900 mg l⁻¹ during late summer (fumigation: late summer; transplant: late-summer/autumn; last harvest: early spring), performed well up to 132.4 kg ha⁻¹ (100 l ha⁻¹). In sandy loam soils with slight F. radicis lycopersici infections and severe infections of F. lycopersici and galling nematodes (M. javanica), 268.4 kg ha⁻¹ (200 l ha⁻¹) of the mixture applied at 900 mg l⁻¹ as a drip provided yields similar to those of methyl bromide treated plots both in spring and summer cycles. In sandy loam soils, the diseases (F. lycopersici, F. radicis lycopersici) were controlled at rates 268.4 kg ha⁻¹ (containing 90 kg ha⁻¹ of chloropicrin), but the mixture was ineffective against Sclerotium rolfsii occasionally observed in sandy loam soils. In both sandy and sandy loam soils, no significant relationships were found between the rates of mixture applied (132.4, 268.4, 402.6 and 536.8 kg ha⁻¹) and the degree of nematode infestation.     

Liquid formulations of seed-treatment fungicides suitable for use on peanuts

Emergence and plant performance were equivalent when peanut seed was treated with either a standard dust or with mixtures of liquid (suspension concentrate) formulations of fungicides applied at rates required to control soil- and seed-borne fungi. Liquid formulations do not pose the health and mechanical problems associated with dusts, so their use should be encouraged and adopted. A suitable treatment consists of a combination of captan 300g/l, dicloran 300g/l, an oil extender and rhodamine dye in acetic acid at 188, 247, 341 and 4 · 6 ml respectively per 100 kg of seed.