Evaluation of integrated crop management strategies employed to cope with Striga infestation in permanent land use systems in southern Benin

Striga hermonthica and S. gesnerioides pose serious threats to cereal and cowpea production, endangering peoples' livelihoods on the Abomey plateau, Benin. A 2-year joint experiment was undertaken with farmers in two hamlets to investigate the potential of managing sowing dates of cowpea, sorghum transplanting, and trap cropping as ways of increasing agricultural production and reducing Striga damage. Early sowing of cowpea failed due to dry spells. Late sowing reduced cowpea yield due to water deficiency at the end of the growing season. Transplanting sorghum seedlings raised in fertilised or Striga-free nurseries doubled or tripled cereal yield and substantially reduced S. hermonthica infestation compared to direct early-sown sorghum. Transplanting sorghum from plant hills to fill gaps was unsuccessful. Trap crops such as cowpea and groundnut increased subsequent maize yield. Trap cropping had only a small effect on S. hermonthica infestation. The very poor soils in Somè central were a major constraint upon yield improvement to acceptable levels even after the introduction of the new crop (and Striga) management methods.     

Combining novel monitoring tools and precision application technologies for integrated high-tech crop protection in the future (a discussion document)

The possibility of combining novel monitoring techniques and precision spraying for crop protection in the future is discussed. A generic model for an innovative crop protection system has been used as a framework. This system will be able to monitor the entire cropping system and identify the presence of relevant pests, diseases and weeds online, and will be location specific. The system will offer prevention, monitoring, interpretation and action which will be performed in a continuous way. The monitoring is divided into several parts. Planting material, seeds and soil should be monitored for prevention purposes before the growing period to avoid, for example, the introduction of disease into the field and to ensure optimal growth conditions. Data from previous growing seasons, such as the location of weeds and previous diseases, should also be included. During the growing season, the crop will be monitored at a macroscale level until a location that needs special attention is identified. If relevant, this area will be monitored more intensively at a microscale level. A decision engine will analyse the data and offer advice on how to control the detected diseases, pests and weeds, using precision spray techniques or alternative measures. The goal is to provide tools that are able to produce high-quality products with the minimal use of conventional plant protection products. This review describes the technologies that can be used or that need further development in order to achieve this goal.     

Preliminary findings of potentially resistant goosegrass (Eleusine indica) to glufosinate‐ammonium in Malaysia

Goosegrass (Eleusine indica), regarded as one of the world's worst weeds, is highly pernicious to cash crop‐growers in Malaysia. Following reports in 2009 that glufosinate‐ammonium failed to adequately control goosegrass populations in Kesang, Malacca, and Jerantut, Pahang, Malaysia, on‐site field trials were conducted to assess the efficacy of glufosinate‐ammonium towards goosegrass in both places. Preliminary screenings with glufosinate‐ammonium at the recommended rate of 495 g ai ha^?1 provided 82% control of the weed at a vegetable farm in Kesang, while the same rate failed to control goosegrass at an oil palm nursery in Jerantut. The ensuing greenhouse evaluations indicated that the “Kesang” biotype exhibited twofold resistance, while the “Jerantut” biotype exhibited eightfold resistance towards glufosinate‐ammonium, compared to susceptible goosegrass populations. The occurrence of glufosinate resistance in goosegrass calls for more integrated management of the weed to prevent escalating resistance and further proliferation of the weed in Malaysia.     

Peanut (Arachis hypogaea) response to weed and disease management in northern Ghana

Weeds and diseases can reduce peanut (Arachis hypogaea L.) yield or increase cost of production to maintain acceptable yield. While herbicides and fungicides have limited availability in many areas of Ghana and currently are too expensive for resource-poor farmers, control by these pesticides can have a major positive impact on peanut yield. Field experiments were conducted during the rainy seasons of 2009 and 2010 in northern Ghana to determine the effects of herbicide and hand weeding in combination with fungicides on pest management and peanut yield. Peanut pod yield was often more highly correlated with disease severity and canopy defoliation resulting from early leaf spot (caused by Cercospora arachidicola Hori) and late leaf spot (caused by Cercosporidium personatum (Berk. & M.A. Curtis) Deighton) than weed biomass. In some instances, less disease and canopy defoliation were observed when weeds were not controlled effectively compared with increased weed management through hand weeding or herbicide. Two hand weedings or applying pendimethalin preemergence with one hand weeding in combination with 4 applications of triadimefon and chlorothalonil resulted in the lowest weed density and canopy defoliation and often resulted in the highest peanut yield.     

Resistance status of cultivated potatoes to early blight (Alternaria solani) in Denmark

Field experiments were conducted in 2015 and 2016 to classify the resistance level to early blight of the main potato cultivars in Denmark. A total of 38 cultivars were used. The experiment was designed as a randomized complete block design (RCBD) with four replicates. The potatoes were inoculated by spreading barley (Hordeum vulgare) kernels infested with Alternaria solani and A. alternata. Disease assessment was done at weekly intervals starting from the onset of the first symptoms. The disease progress curves (DPC) of early blight on the cultivars were compared to that of Bintje. A multivariate analysis was performed with the apparent infection rate, the relative area under the disease progress curve, the time to reach 50% severity, the daily defoliation, the disease severity in the middle of the epidemic and the duration of the epidemic to classify the resistance level of the cultivars. The analysis of the DPC of the cultivars showed that none of the cultivars was completely resistant to early blight. However, the epidemic development differed between the different cultivars. The resistance levels of the cultivars were thus classified into classes I, II, III and IV interpreted as ‘very susceptible’, ‘susceptible’, ‘moderately slow blighting’ and ‘slow blighting’, respectively. All the late maturity cultivars were classified as class IV, and the earlier maturing cultivars were either class I or class II.     

Common oils and insecticidal control and their resistance to Aleuroclava jasmini (Hem.: Aleyrodidae) on paper mulberry in Iran

Abstract

Aleuroclava jasmini (Hemiptera: Aleyrodidae) is a major insect pest of paper mulberry (Broussonetia papyrifera) in Iran, negatively affecting its production. Considering the importance of oils in the integrated management programs of such pests, the present study examined the possibility of whitefly control on paper mulberry plant to assess mortality rate (MR), synergistic rate (SR), resistance rate (RR), and lethal concentration for 50% of the population (LC₅₀) of oils and common insecticide in populations from four areas of Tehran, Iran (one susceptible and three non-susceptible). The best chemical treatments against A. jasmini adults and nymphs in paper mulberry plants were neem oil (1?ml L^?1) mixed with deltamethrin (0.5?ml L^?1) or with buprofezin (1?ml L^?1). The neem, akylarylpolyglyglycol ether and volk oils mixed with deltamethrin or buprofezin also had synergistic effects on adults and nymphs of A. jasmini, respectively, in Azadi, Shahrake Gharb, and Vanak areas (non-susceptible populations), but with higher concentrations (> LC₅₀) and lower SR than in Garm Dareh area (susceptible population). We observed that A. jasmini adults showed the greatest resistance to deltamethrin in Vanak area and nymphs of this pest to buprofezin in Shahrake Gharb area.     

An Experiment to Assess Losses Caused by Frit-fly (Oscinella frit L) Shoot Attack and the Application of Phorate in a Crop of Sweet Corn (Zea mays L)

Wilt caused by the fungus Fusarium oxysporum f. sp. ciceris adversely affects the productivity of cultivated chickpea. For the management of this disease, seed and soil application formulations developed from another fungus, Trichoderma species, were evaluated. In pot experiments, T. harzianum-based formulations Pusa 5SD for seed dressing and Pusa Biopellet (PBP) 10G and Pusa Biogranule (PBG) 5 for soil application, and T. viride-based formulations Pusa 5SD for seed dressing and PBP 4G and PBG 4 for soil application, were found to be highly effective against the disease. A combination of PBP 4G (T. viride) for soil application and Pusa 5SD (T. harzianum) for seed treatment together with a fungicide, carboxin, provided the highest seed germination, shoot and root lengths and grain yield with the lowest incidence of wilt in chickpea under field conditions. Individually, soil application of PBP 4G, and seed treatment with Pusa 5SD were effective in reducing the incidence of wilt and increasing the grain yield of chickpea, but their effectiveness was greater when applied as a combination. Thus, combined application of the formulations of two different species of Trichoderma in two modes of application is recommended for the management of chickpea wilt.     

Control of Schistosomiasis (Bilharziasis) in Brazil,Past, Present and Future

Abstract

Schistosoma mansoni was first recorded in Brazil in 1908, currently official estimates are that schistosomiasis is endemic in 1,000 municipalities and possibly ten million individuals are infected. Infection foci are rural communities and irrigated areas without sewage disposal facilities. In the past The Servicio Especial de Saúde Publica: The Servico Nacional de Malaria and later the Department of Rural Endemic Diseases (DNERu) attempted with some success to control the intermediate hosts, Biomphalarla spp., and improve sanitation and water supplies. Following examination of past policies DNERu in 1965 authorised the organisation of pilot projects for the control of schistosomiasis in 4 states: Pernambuco, Bahia, Minas Gerais, and Gaunabara. In 1970 the results of the pilot projects were evaluated and recommendations made regarding drug treatment and snail control for immediate use by the Superintendencia de Campanhas of the Federal Ministry of Health, involving the use of the drug Hycanthone, the molluscicide niclosamide (Bayluscide) and complimentary measures such as drainage and education in basic sanitation. In the future with the greater urbanisation of Brazil and increasing number of irrigation projects the incidence of the disease could increase. Improvements in sanitation, education and nutritional state will counteract this.     

Mechanisms of resistance to organophosphorus insecticides in populations of the obliquebanded leafroller Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) from southern Ontario

Populations of Choristoneura rosaceana (Harris) from orchards in Ontario were shown to be resistant to azinphos-methyl and to other types of organophosphorus insecticides. Resistance extended to methyl carbamates and to methomyl. The laboratory population used for these assays and selected with azinphosmethyl was also resistant to the pyrethroid, cypermethrin. Resistance was associated with increased esterase activity and was reduced by the addition of the synergist DEF. IEF studies of esterases also indicated increased activity in resistant populations, but did not identify any unique esterases associated with the resistance. Resistance was highly correlated (r = 0.78) with elevated esterases but not with increased glutathione-S transferase activity (r = 0.13). Other mechanisms did not appear to be related.