Root diseases, weeds, and nematodes with poultry litter and conservation tillage in a sweet corn–snap bean double crop

The effect of continuous applications of poultry litter on root diseases, nematodes, and weeds with different tillage practices in vegetable production in Georgia was investigated. Litter treatments (noncomposted and composted broiler or breeder litter) applied 3–5 weeks before planting were compared with no litter. In sweet corn and snap bean there were differences among years, and tillage and litter treatments had a variable effect on yield, post-emergence damping-off and plant stand. Crown and brace root rot in corn induced by Rhizoctonia solani AG 2-2 increased after 3 years conservation tillage, but there were no differences among litter treatments. Population densities of R. solani AG-4 were increased by conservation tillage before planting snap bean the first year but not in later years, while litter treatments had no effect. After 3 years, populations of Pythium spp., Fusarium solani, and Fusarium spp. did not differ among treatments, but noncomposted broiler litter increased populations of saprophytic fungi in soil compared with no litter. Population densities of stylet-bearing nematodes were low and usually not different among treatments. After 3 years of sweet corn populations of Meloidogyne incognita increased with conventional tillage compared with conservation tillage, populations of Paratrichodorus christiei were reduced by litter treatments and populations of Helicotylenchus dihystera were reduced by noncomposted broiler litter compared with no litter. Weed infestation increased in both tillage systems with time, but in snap bean there was a greater infestation in conservation tillage than in conventional tillage. Litter treatments had little effect on weed infestation.     

Influence of chemical seed and soil treatments onVerticillium-induced yield reduction and tuber defects

Experiments were conducted in 1969 and 1970 to determine the influence of chemical treatments of seed pieces and soil on the development ofVerticillium wilt as measured by tuber yield increases and reduction in severity of tuber defects. The influence of storage onVerticillium-induced tuber defects was evaluated. Seed treatment chemicals tested included zinc ion maneb, maneb, maneb-chloroneb, Polyram, benomyl, and thiabendazole. Soil treatment chemicals included O-Diethyl (O-methyl-sulfinyl) phenyl phosphoro-thioate, disulfoton, phorate, carbofuran, aldicarb, ethyl 4 (methyl- thio)-m-tolyl isopropyl phosphor amidate, benomyl, and thiabendazole. Inoculated seed pieces and artificially infested plot areas were used the first year while the second year natural inoculum from a previous crop was the source of infection. Kennebec and Katahdin cultivars were tested in 1969 and Kennebec alone in 1970. Verticillium-induced yield reductions and tuber defects were more severe in all respects with Kennebec than with Katahdin. With Katahdin the only significant evidence of infection was stem end discoloration. Seed treatments, with the exception of benomyl or thiabendazole, which were erratically phytotoxic, resulted in consistent yield increases and reduction in pink eye severity. In 1969 seed treatment reduced stem end browning in Kennebec. Soil treatment with disulfoton, carbofuran, and aldicarb, both alone and in combination with seed treatments resulted in consistent yield increases with Kennebec. The seed piece and soil treatment combinations tested in 1970 appeared to have an additive effect on yield increase from combination treatments equivalent to the gain from soil treatment alone plus seed treatment alone. The nematicide soil treatment materials did not influence yield. Tuber stem-end browning and pink eye defects in Kennebec did not increase in severity over a five month storage period.     

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.     

Control of cotton bollworms with fenvalerate in India

The synthetic pyrethroid fenvalerate (Sumicidin^® 20E¹) has been tested in 64 field trials of the control of bollworms on rainfed and irrigated cotton in Maharashtra, Tamil Nadu, Punjab, Andhra Pradesh, Haryana, Rajasthan, Madhya Pradesh, Gujarat and Karnataka. Fenvalerate, at dose levels of 50–150 g a.i./ha, was tested on 15 varieties of cotton, with long, extra-long, short and medium staples. From two to nine sprays were applied at intervals of 7–30 days, depending on whether the insecticide was sprayed according to a calendar-based schedule or when needed. Fenvalerate was compared with conventional insecticides such as carbaryl, monocrotophos, endosulfan and phosalone, and also with the synthetic pyrethroids permethrin, cypermethrin and deltamethrin. The percentage of bollworm-infested plants in the fenvalerate-treated plots ranged from zero to 21·8% and in the untreated plots was up to 100%. With conventional pesticides the maximum level of infestation was 97·2%. Increases in yield of seed cotton from fenvalerate-treated plots over those from plots treated with conventional pesticides were 54%, 57%, 67%, 84%, and 86% over monocrotophos, carbaryl, quinalphos, phosalone and endosulfan, respectively, representing increases of 791–1046 kg/ha.     

Row treatment of potatoes with systemics for meadow nematode (Pratylenchus penetrans) control

Granular aldicarb and carbofuran, systemic carbamate insecticides, were applied at 3 lbs active per acre to compare their control of the meadow nematode (Pratylenchus penetrans). These systemic pesticides were applied either in two bands 2–3 inches from both sides of and at the lower plane of the seed-piece or in one band 4–5 inches wide and 1/2 inch above the seed. Two months after planting, nematode populations were greatly reduced in soil and roots from plots treated with either chemical and with both placement methods. Aldicarb provided effective control longer into the growing season than did carbofuran. When compared with carbofuran, aldicarb-treated potao plants lived longer and produced a greater increase in yield over the untreated plots. Yield increases were greater when either systemic was applied in side bands than when placed over the seed.     

The control of weed,pest and disease complexes in cowpea (Vigna unguiculata (L.) Walp.) by the application of pesticides singly and in combination

Several pesticides were evaluated singly and in combination or mixtures for their effectiveness against insects, nematodes, diseases and weeds in cowpea at Ibadan and Amakama in Nigeria. Of the granular insecticides/nematicides, carbofuran at 3·0 kg a.i./ha applied at planting reduced the population of thrips (Megalurothrips sjostedti) below control level up to 42 days after planting, but did not appear to translocate to the pods. Ethoprofos, isazophos and phorate were ineffective against thrips. Carbofuran also showed excellent control of the root-knot nematode, Meloidogyne incognita. The herbicides metolachlor and fluorodifen generally kept the plots weed-free up to 35 days after planting but had no effect on the nematodes. The fungicide benomyl applied as a seed treatment was not effective against web blight (Corticium solani) and brown blotch (Colletotrichum truncatum) but, when applied as a wettable powder in combination with monocrotophos as a foliar spray, offered effective control of the diseases and the combination gave the best grain yield across locations. The possible use of carbofuran with a cowpea variety that is resistant to larvae of the pod-boring moth (Maruca testulalis) is discussed.     

Morphological and Genetical Variability among Rhizoctonia solani Isolates Causing Sheath Blight Disease of Rice

Eighteen isolates of Rhizoctonia solani collected from infected rice plants in four different locations of Bangladesh were studied by using morphological characters and molecular markers. Anastomosis study with a reference isolate confirmed that all the isolates belonged to R. solani. Significant variation was observed in sclerotial size, shape and distribution. Un-weighted pair group method with arithmetic mean dendrogram constructed based on the Gower's general similarity coefficient showed that these isolates were grouped into four clusters at the 0.68 similarity coefficent according to morphological characters. Cluster I was a major cluster consisting of 13 isolates, while clusters Ⅱ to Ⅳ consisted of 1 or 2 isolates. Analyses by variable number of tandem repeat and amplified fragment length polymorphism markers showed that the isolates were grouped into five and three clusters at a similarity coefficient of 0.64 and 0.69, respectively. Although most of the variability was found between isolates from different regions as expected, significant variation was observed within the isolates collected from similar agro-ecological regions. Our results suggest the presence of different races of R. solani within the same local geographic regions.     

Influence of treatment of soil with carbofuran on the subsequent performance of insecticides against cabbage root fly (Delia radicum) and carrot fly (Psila rosae)

A sandy loam soil was treated with 2·5 kg carbofuran/ha on each of five occasions between May and October 1984. In 1985, the field performance of benfuracarb, carbofuran, carbosulfan, chlorfenvinphos and furathiocarb against cabbage root fly (Delia radicum) and carrot fly (Psila rosae) was studied in this soil and in identical but previously untreated soil by applying exponentially increasing doses of granular formulations to radish and carrots at drilling. Chlorfenvinphos reduced numbers of larvae of both pests by >90% in both soils but the performance of all the carbamates was significantly worse in the previously treated soil than in the previously untreated soil. Dazomet, a partial soil sterilant, was applied to part of the experimental area in October 1985 and the performance of aldicarb, carbofuran, carbosulfan, chlorfenvinphos and thiofanox against cabbage root fly was assessed in 1986. The efficiency of aldicarb and chlorfenvinphos was not affected by any of the pre-treatments but that of carbofuran and carbosulfan was reduced in all the pre-treated soils, including the soil treated with dazomet. Carbofuran residues in radish were detectable only in plants grown in previously untreated soil. In laboratory incubations, a dustless base formulation of carbofuran was degraded more quickly in pre-treated than in untreated soils but a granular formulation was degraded more slowly and at a similar rate in both soils.     

Insecticides for control of potato tuberworm and green peach aphid on potatoes in California

Six insecticides were evaluated in a replicated field experiment at Gonzales, California, for control of the potato tuberworm,Phthorimaea operculella (Zeller), and the green peach aphid,Myzus persicae (Sulzer). Azodrin^®, methomyl, Stauffer N 4543 (O-isobutyl ethylphosphonodithioate S-ester with N-(mercaptomethyl) phthalimide) and azinphosmethyl were applied as foliage sprays by ground sprayer at 2-week intervals. The systemic insecticides, aldicarb (Temik^®) and carbofuran (Furadan^®) formulated as 10% granules, were applied to the soil as side dress treatments on the same day that the spray treatments were begun. Aldicarb granules were also applied topically so that the granules fell on the young plants and on the soil surface. Azinphosmethyl, Stauffer N 4543, Azodrin^® and methomyl effectively controlled the tuberworm larvae in the foliage but effective control of tuberworms in the harvested tubers occurred only where azinphosmethyl, methomyl and Stauffer N 4543 were used. The granule applications of carbofuran and aldicarb were totally ineffective in controlling the potato tuberworm. Effective green peach aphid control was obtained with Azodrin^® spray and the two granular aldicarb treatments. The side dressed application of aldicarb appeared to provide better green peach aphid control than did the soil surface application.     

Chemical control of Delia platura in Phaseolus vulgaris with seed and soil treatments in Chile

A field trial with beans (Phaseolus vulgaris L.) was performed in the Santiago area, to evaluate the insecticidal effect of aldrin, carbofuran, chlorpyriphos, diazinon and lindane, applied to the seed or to the seed furrow, against the bean fly, Delia platura Meigen (Diptera, Anthomyiidae). Plant emergence was reduced with carbofuran and diazinon as a seed treatment, and chlorpyriphos in the furrow, in relation to the checks. All insecticidal treatments reduced the damage to the plants, demonstrating the value of using insecticides for controlling this pest.     

Concentrations in soil and efficacy of drip-applied 1,3-D+chloropicrin and metam sodium in plastic-mulched sandy soil beds

Concentrations in soil and efficacy of 1,3-dichloropropene (1,3-D)+chloropicrin and methyl isothiocyanate (MITC) against the survival of Phytophthora capcisi, Rhizoctonia solani and yellow nutsedge (Cyperus esculentus L.) were studied in plastic-mulched Southern Georgia sandy soil beds. Beds were treated with InLine (60.8% 1,3-D+33.3% chloropicrin) at 93.5, 187, and 280.5 l ha⁻¹ and Vapam (42% metam sodium) 233.8, 467.5 and 701.3 l ha⁻¹. 1,3-D+chloropicrin and MITC concentrations in soil were monitored after drip application for 7 d and 240 h, respectively, from pre-selected sites in beds. 1,3-D+chloropicrin and MITC concentrations decreased with time and distance from the emitter. Survival of P. capsici, R. solani and yellow nutsedge in treated beds was higher with distance from the emitter. These methyl bromide alternatives did not diffuse laterally at effective concentrations beyond the point of application. Improved application techniques are required to improve the lateral distribution of these alternatives.     

Effect of a combination of chlorine dioxide and thiophanate-methyl pre-planting seed tuber treatment on the control of black scurf of potatoes

The pre-planting seed tuber treatments of chlorine dioxide (ClO₂), thiophanate-methyl (TPM), and a combination treatment of ClO₂, followed by TPM, were evaluated for control of stem canker and black scurf (Rhizoctonia solani), and storage rots; black scurf, common scab (Streptomyces scabies), dry rot (Fusarium spp.) and silver scurf (Helminthosporium solani) on potato (Solanum tuberosum L.) cv. Kennebec. Field experiments were conducted in two consecutive years, 1999 and 2000, at the Agriculture and Agri-Food Canada Research Farm in Harrington, Prince Edward Island (PEI), Canada. The combination treatment of ClO₂ (200 μg g⁻¹) and TPM (50 g active ingredient100 kg⁻¹ of tubers) significantly (P=0.05) reduced stem canker and black scurf on progeny tubers at harvest and after storage. The low incidence of scab and dry rot in untreated controls hindered the evaluation of the efficacy of the combination treatment and also showed that conditions were not favourable for disease development during this period at Harrington. The combination treatment was not effective on silver scurf in storage. A comparison among control, ClO₂, TPM, and the combination treatment indicates that pre-planting ClO₂ treatment may have killed the majority of the black scurf sclerotia on the tuber surface and that the combination of TPM fungicide treatment following ClO₂ treatment gave protection to progeny tuber by suppressing the growth of the R. solani. A higher marketable yield was observed in the combination treatment as compared with the untreated control. Phytotoxicity was not observed in tubers treated with the combination treatment.     

Controlled-release insecticide granules, compared with other soil insecticides, for use against the termite, Macrotermes natalensis Haviland, in the establishment of Eucalyptus plantations

Following the banning of DDT and dieldrin, and pending the withdrawal of other organochlorine insecticides in many countries, there is a need to find alternative treatments against termites for the establishment of Eucalyptus forestry plantations. Controlled-release granules (CRG) of carbosulfan, carbofuran and phorate were nearly as effective as chlordane emulsifiable concentrate (0·6 g a.i./tree) in reducing attack on Eucalyptus grandis W. Hill ex Maiden by Macrotermes natalensis Haviland. The optimum application rate of CRG formulations was 1·0 g a.i./tree mixed with the surrounding soil at planting out. Changes in granule size and release rate had no discernable effect on the efficacy of the granules, nor was there any advantage in incorporating part of the dose in the seedling planting medium. Chlorpyrifos CRG was significantly less effective in protecting the trees. There was evidence that under dry soil conditions phorate CRG was ineffective. Of 11 other non-controlled-release insecticides tested, alphamethrin suspension concentrate at 0·1 g a.i./tree was the only non-organochlorine material as effective as the CRG formulations.     

木薯根系分泌物与土壤浸出液对橡胶树2种致病菌的化感效果

采用平板试验,通过生长速率法分析木薯根系分泌物及其土壤浸出液对橡胶树白根病病菌及棒孢霉落叶病病菌的化感效果,为判断胶园林下种植木薯的可行性提供理论依据。结果表明：（1）木薯根系分泌物对橡胶树白根病和棒孢霉落叶病病菌均表现为化感促进效果,但在任一处理时间,不同浓度间对白根病病菌的化感效果与对照均未达显著差异,而对棒孢霉落叶病病菌的化感效果呈现明显的剂量效应,浓度达40 mg/mL时,化感促进效果与对照达到显著水平。（2）木薯根系分泌物的任一浓度,对橡胶树白根病和棒孢霉落叶病病菌的化感效果,在不同处理天数间均未达到显著水平。（3）木薯土壤浸出液对橡胶树白根病和棒孢霉落叶病病菌均呈现化感促进效果,且存在明显的剂量效应;对橡胶树白根病病菌,处理后2 d,达到显著化感效果所需浸出液浓度至少为40 mg/mL,处理后3 d和处理后4 d,达到显著化感效果所需浸出液浓度至少为8 mg/mL;对棒孢霉落叶病病菌,在任一处理时间达到显著化感效果的浸出液浓度均至少为200 mg/mL。（4）土壤浸出液小于8 mg/mL时,3个处理时间之间的橡胶树白根病病菌化感效果无显著差异,当浓度达到40 mg/mL时,处理后2 d的化感促进效果显著大于处理后3 d和4 d;4种土壤浸出液的任一浓度,对橡胶树棒孢霉落叶病病菌的化感效果在不同处理时间之间均未达到显著差异。所以说,幼龄胶园间作木薯会在一定程度上促进橡胶树棒孢霉落叶病和白根病的发生。     

Insecticide control of the potato tuberworm in late-crop potato foliage

The systemic insecticides, Dasanit^®, carbofuran (Furadan^®), phorate (Thimet^®), aldicarb (Temik^®) and disulfoton (Di-Syston^®) were applied in the planting furrow at 2–3 lb actual/acre for potato tuberworm (Phthorimaea operculella (Zeller)) control in Irish potato foliage. None of these compounds gave entirely satisfactory results. Dasanit was the best with slightly over 80% decrease in the number of mines and was followed closely by carbofuran; all treatments needed to be supplemented by foliage sprays for satisfactory tuberworm protection. Azinphosmethyl (Guthion^®) gave consistently outstanding results as a foliage spray at 0.5 lb/acre with over 99% tuberworm reduction. Other foliar-applied insecticides giving at least 98% tuberworm control included: Monitor^®, monocrotophos (Azodrin^®), phosphamidon, Orthene^®, Torak^®, methomyl (Lannate^®) and Dursban^® (all at 0.5 lb/acre) and Phosvel^® (1 lb/acre).     

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.     

萎锈灵在大麦和土壤中的残留及安全性评价

为探明萎锈灵在大麦上的残留特性和安全性,通过田间试验和室内检测,研究了萎锈灵在大麦和土壤中残留的检测方法、萎锈灵在土壤中的消解动态及其在大麦和土壤中的最终残留量。结果表明,本检测方法对萎锈灵的最小检出量为0.002ng,萎锈灵在大麦植株、籽粒和土壤中的最低检测浓度分别为0.005、0.002、0.001mg·kg~(-1),添加回收率分别为78.9%~94.0%、92.4%~98.6%和90.6%~101.3%;相对标准偏差分别为1.3%~7.9%、1.8%~4.7%和0.9%~4.8%。萎锈灵在土壤中的半衰期为6.5~7.1d,药后14d消解率大于93%。400g·L~(-1)萎锈·福美双悬浮剂120、180g a.i.·100kg~(-1)种子拌种,收获期大麦籽粒中萎锈灵残留量均低于0.002mg·kg~(-1),说明400g·L~(-1)萎锈·福美双悬浮剂在大麦上使用是安全的。     

Nematodes and fungal diseases in barley and wheat on Prince Edward Island

A total of 31 genera and 28 species of plant and soil nematodes were identified from 30 commercial fields each of barley and wheat on Prince Edward Island. Root-lesion nematodes, primarily Pratylenchus penetrans, were the dominant plant parasites, and the only endoparasitic nematodes recovered from roots. Root-lesion nematodes were the dominant genus in soil, but stunt nematodes (Tylenchorhynchus spp., primarily T. dubius, and Merlinius spp.), and pin nematodes (Paratylenchus spp.) were also recovered frequently. Common root rot, barley net blotch, and wheat leaf blotch, incited by Cochliobolus sativus, Pyrenophora teres, and Leptosphaeria nodorum, respectively, were prevalent in barley and wheat. The nematicide aldicarb reduced the numbers of root-lesion nematodes in roots and soil in experimental plots during 1984–1987, except from soil in wheat and barley in 1984 and in barley in 1986. Aldicarb treatments also increased grain yields significantly by 10% and 19% in 1984 and 1987, respectively. Aldicarb treatments did not affect the incidence of common root rot, barley net blotch, or wheat leaf blotch disease. Correlation and regression analyses of data from experimental plots did not indicate any significant relationships between population levels of root-lesion nematodes in roots or soil and severity of root or foliar diseases in barley or wheat.     

6株生防细菌对大豆根腐病防治效果初步评价

从大豆根际分离出的1500多株细菌中筛选出6株生防细菌,其在离体的条件下对大豆根腐病病原菌尖孢镰刀菌(Fusarium oxysporum)有很好的抑制作用,其中菌株18BRR2-2、18BRR9-1和3BRR16-2在离体的条件下也对茄腐镰刀菌(F.solani)、半裸镰刀菌(F.semitectum)和立枯丝核菌(Rhizoctonia solani)有抑制作用,并且这6株生防细菌的发酵液可以抑制尖孢镰刀菌(F.oxysporum)的生长.通过温室盆栽和大田试验表明,这些生防菌对大豆根腐病有很好的防治效果,其中菌株18BRR2-2盆栽和大田的防效均最高,分别达到了45.9%和65.00%.而且这些生防菌也表现出对大豆明显的促生作用.认为18BRR2-2号菌株有开发为防治大豆根腐病生防制剂的潜力.     

Phytotoxicity of lemon-scented eucalypt oil and its potential use as a bioherbicide

The effect of volatile oil from leaves of Eucalyptus citriodora against some plant species viz. Triticum aestivum, Zea mays, Raphanus sativus, Cassia occidentalis, Amaranthus viridis and Echinochloa crus-galli was investigated. In a laboratory bioassay seed germination of test plants was significantly reduced in response to the different concentrations of the eucalypt oil. Maximum germination inhibition was observed with A. viridis, whereas least effect was seen on R. sativus. Based on the germination response, dose-response curve was generated and LC₅₀ values were calculated. It was maximum for R. sativus whereas minimum for A. viridis. Further, seedling growth of the test plants and the chlorophyll content in the treated seedlings was significantly reduced at concentrations 0.12 and 0.3 mg/l. Not only the initial growth, but also the spray treatment on the 4-week-old mature plants of two weedy species viz. C. occidentalis and E. crus-galli adversely affected the chlorophyll content and cellular respiration, thereby indicating the adverse effect of eucalypt oil on the photosynthetic machinery and the energy metabolism of the target plants. Based on the study, it is concluded that volatile oil from E. citriodora is phytotoxic and could be utilized as bioherbicide for future weed management programmes.