Occurrence and Control of Plant-parasitic Nematodes in Irrigation Water – A Review

A literature study was carried out to determine what is currently known about the contamination of irrigation water withplant-parasitic nematodes, and what control measures are currently available. Contamination sources of irrigation waterwith plant-parasitic nematodes were investigated, including wells, boreholes, collected rainwater, ponds, lakes, dams,rivers, municipal water, runoff water, irrigation canals and drainage water in soilless culture. Only when the origin ofirrigation water was a capped borehole was the risk of contamination with plant-parasitic nematodes low. The plantparasiticnematodes of economic importance to grapevine reported to be found in irrigation water were Meloidogynespp., Xiphinema spp., Tylenchulus semipenetrans, Trichodorus sp., Criconemoides xenoplax and Pratylenchus spp. Thedifferent sampling techniques used for the detection and monitoring of plant-parasitic nematodes and the sampling timeand location are listed. The survival and infection potential reported for each species of plant-parasitic nematode found inirrigation water was noted. Serious nematode parasites of grapevines, such as Meloidogyne javanica, can survive for 16 to32 days, M. incognita, for up to 14 days, Pratylenchus, for up to 70 days, T. semipenetrans, for up to 128 days, and X. index,for up to 13 days in irrigation water. All reported techniques used for the management of nematodes in irrigation water arelisted and possible future research into the control of plant-parasitic nematodes in irrigation water is discussed. From thisreview, substantial evidence was obtained of the danger of introducing plant-parasitic nematodes to grapevine productionsites by means of irrigation water

Formulation of Entomopathogenic Nematodes for the Control of Key Pests of Grapevine: A Review

Entomopathogenic nematodes (EPNs) are insect parasites that are used successfully as biological controlagents against key pest insects of grapevine. To achieve low chemical residues and the sustainableproduction of grapes, it is important that biological control agents such as entomopathogenic nematodesfor the control of grapevine insect pests be incorporated in an integrated pest management system forgrape production. However, the commercialisation and large-scale use of EPNs is limited by their shortshelf life in formulations and in storage, thus leading to poor quality and reduced efficacy against insectsin the field. In South Africa, interest in the use of EPNs within an integrated pest management system hasgrown over the past two decades, therefore developing a formulation technique with an acceptable storagesurvival period, while maintaining infectivity, is essential. Moreover, the successful control of insects usingEPNs is only achievable when the formulated product reaches the end user in good condition. This reviewis focused on the different types of formulations required for storage and ease of transport, together withthe application formulation for above-ground pests and the factors affecting them. The quality assessment,storage and handling of formulated EPNs are also discussed

Prospects for Using Entomopathogenic Nematodes to Control the Vine Mealybug, Planococcus ficus, in South African Vineyards

In South Africa, the most common method of mealybug control has been the use of chemical insecticides.Entomopathogenic nematodes (EPNs) of the of the families Heterorhabditidae and Steinernematidaepotentially can be used within an integrated pest management scheme to control Planococcus ficus, the vinemealybug, which occurs on all parts of grapevine, including the roots. When Steinernema yirgalemensewas applied to the soil of two vineyards with P. ficus, contained in pierced Eppendorf tubes, buried ata depth of 15 cm in the soil, mortalities of up to 50% were obtained after 48 h. The persistence of S.yirgalemense, measured using codling moth larval mortality was found to be zero in one vineyard, whilein the other it was 70%, 12 weeks after application. Tests were conducted to establish the production ofscavenger deterrent factors by H. zealandica and S. yirgalemense. Of the cadavers that were presentedsix days after nematode infection, 49% of the H. zealandica- and 60% of the S. yirgalemense-infectedcadavers were left intact. Olfactometry tests indicated a significant difference concerning the number ofS. yirgalemense infective juveniles (IJs) that were attracted to damaged Vitis vinifera roots and P. ficus,indicating active movement of the IJs and the attractive ability of organic compounds produced by theroots. This study shows that EPNs, and specifically S. yirgalemense, have promising potential as biologicalcontrol agents for the control of P. ficus soil populations, and investigates some influential factors affectingEPNs as biocontrol agents in the agro-ecosystem

The Potential Use of Entomopathogenic Nematodes to Control Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae)

Laboratory bioassays were conducted to establish the potential of entomopathogenic nematodes (EPNs) asbiocontrol agents of Planococcus ficus (Signoret). Six indigenous and two commercially available nematodespecies were screened for their efficacy in killing adult female P. ficus. The two indigenous species withthe most promising results were Heterorhabditis zealandica and Steinernema yirgalemense, which wereresponsible for 96% and 65% mortality respectively. Tests were conducted to compare the efficacy ofH. bacteriophora and S. feltiae produced in vivo and in vitro. Heterorhabditis bacteriophora showed nosignificant difference in efficacy between the two production methods, but in vivo-cultured S. feltiaeproduced a significantly higher mean mortality of 40%, in contrast to a 19% mean mortality with in vitroproducedinfective juveniles (IJs). The capability of both H. zealandica and S. yirgalemense to completetheir life cycles in the host and to produce a new cohort of IJs was demonstrated. Bioassays indicateda concentration-dependent susceptibility of P. ficus to H. zealandica, S. yirgalemense and commerciallyproduced H. bacteriophora, with LC50 and LC90 values of 19, 82; 13, 80; and 36, 555 respectively. Both H.zealandica and S. yirgalemense were able to move 15 cm vertically downward and infect P. ficus with arespective mortality of 82% and 95%. This study showed P. ficus to be a suitable host for H. zealandicaand S. yirgalemense, with both nematode species showing considerable potential for future use in the fieldcontrol of P. ficus

The Potential Use of Entomopathogenic Nematodes to Control Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae)

Laboratory bioassays were conducted to establish the potential of entomopathogenic nematodes (EPNs) asbiocontrol agents of Planococcus ficus (Signoret). Six indigenous and two commercially available nematodespecies were screened for their efficacy in killing adult female P. ficus. The two indigenous species withthe most promising results were Heterorhabditis zealandica and Steinernema yirgalemense, which wereresponsible for 96% and 65% mortality respectively. Tests were conducted to compare the efficacy ofH. bacteriophora and S. feltiae produced in vivo and in vitro. Heterorhabditis bacteriophora showed nosignificant difference in efficacy between the two production methods, but in vivo-cultured S. feltiaeproduced a significantly higher mean mortality of 40%, in contrast to a 19% mean mortality with in vitroproducedinfective juveniles (IJs). The capability of both H. zealandica and S. yirgalemense to completetheir life cycles in the host and to produce a new cohort of IJs was demonstrated. Bioassays indicateda concentration-dependent susceptibility of P. ficus to H. zealandica, S. yirgalemense and commerciallyproduced H. bacteriophora, with LC50 and LC90 values of 19, 82; 13, 80; and 36, 555 respectively. Both H.zealandica and S. yirgalemense were able to move 15 cm vertically downward and infect P. ficus with arespective mortality of 82% and 95%. This study showed P. ficus to be a suitable host for H. zealandicaand S. yirgalemense, with both nematode species showing considerable potential for future use in the fieldcontrol of P. ficus

An Overview of the Vine Mealybug (Planococcus ficus) in South African Vineyards and the Use of Entomopathogenic Nematodes as Potential Biocontrol Agent

The vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae), which is the dominant mealybugspecies in South Africa, is a severe wine and table grape pest and disease vector. Their increasingresistance to chemical pesticides and cryptic lifestyles have led to the search for new control methods.Entomopathogenic nematodes (EPNs) belonging to the families Heterorhabditidae and Steinernematidaeare deadly insect pathogens. This paper gives valuable background information on P. ficus and EPNs,while paying particular attention to the potential use of South African EPN species as biocontrol agentsagainst P. ficus

Wool studies II : the frequency distribution of Merino wool fibre thickness measurements

The logarithmic nature of distributions in wool fibre thickness measurements has been suggested by the constancy of the coefficient of variability in previous work. The distribution of a variable, the logarithm of which normally distributed, is discussed. The application of what is in the text called the logarithmic function to 18 different samples is given and the "fit" compared with that of the normal distribution. Two further samples, which were also measured by an antilogarithmic scale, are included and show that the logarithms of fibre thicknesses are normally distributed. The logarithmic nature of the distributions of fibre thickness measurements and the normality of the logarithms of such measurements are illustrated by Figures 1, 2, 3 and 4 respectively. It is suggested that the logarithms of fibre thickness measurements be used for statistical analysis. This would mean that the arithmetical mean is to be replaced by the geometrical mean to represent average fibre thickness.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Includes bibliographical referencesab201

Cover Crops with Biofumigation Properties for the Suppression of Plant-Parasitic Nematodes: A Review

Plant-parasitic nematodes are a problem in vineyards worldwide, with some species acting as vectors ofgrapevine soil-transmitted viruses. Global pressure on the use of soil-applied chemical nematicides hasled to a search for new control options, or for alternative methods to suppress plant-parasitic nematodesas part of integrated pest management. This paper gives valuable background information on the use ofcover crops with biofumigation properties for the suppression of plant-parasitic nematodes in vineyards

Effect of Management Practices Applied to Cover Crops with Biofumigation Properties on Cover Crop Performance and Weed Control in a Vineyard

This five-year trial (2009 to 2013) was carried out in a full-bearing seven-year-old Shiraz/101-14vineyard established on a sandy to sandy clay loam soil at Blaauwklippen farm (33°58’S, 18°50’E) nearStellenbosch, South Africa. Fourteen treatments were applied, consisting of two management practicesapplied to five cover crop species, winter-growing weeds (no cover crop), and winter-growing weeds (nocover crop) combined with a nematicide application in the vine row. The dry matter production (DMP)increased between 0.55 and 2.62 t/ha from 2009 to 2010 for the small-seeded Sinapis alba cv. Braco (whitemustard), Brassica napus cv. AVJade (canola), Brassica juncea cv. Caliente 199 (Caliente) and Erucasativa cv. Nemat (Nemat). This was attributed to the finer seedbed that could be created. All cover cropssuppressed the winter-growing weeds throughout the study. Although the stand of summer-growingweeds differed significantly between treatments in 2010, 2011 and 2012, the cover crop treatments did notsuppress these weeds significantly. However, for the duration of the study, the weed stand in the canolacontrolled chemically full surface (CC) during grapevine bud break tended to be lower than that of thecanola controlled mechanically (MC) during grapevine bud break. The same trend occurred between CCand MC for Avena sativa cv. Pallinup (Pallinup oats) and the treatments in which no cover crops weresown, with the exception of in 2009 and 2010 respectively

Options for Soil Health Measurement in Vineyards and Deciduous Fruit Orchards, with Special Reference to Nematodes

Soil is a non-renewable resource and supports all land-based forms of life. The sustainable productionof crops is becoming progressively more critical as human populations increase and viable agriculturalland decreases. Soil health plays an indispensable part in the sustainability of soil as a resource for futuregenerations. For this very reason it is important to have suitable tools to measure the improvement ordeterioration of soil health in vineyards and orchards. In this review, the use of different bio-indicators toindicate soil health will be discussed, with special emphasis on the use of nematode population structureand function as indicators of soil health. The use of nematodes as a bio-indicator of soil health can play acrucial role in the establishment of future sustainable production of grapes and fruit in the Western Cape.This paper provides a comprehensive review of soil health, the use of different biological indicators, andthe potential of nematodes as suitable indicators thereof, aimed at vineyards and deciduous fruit orchards