"Numerous studies on the interaction between soil borne plant pathogens and phytoparasitic nematodes both on vegetables and fruit trees have been conducted. In the last two decades, in several areas of the R. Moldova, devoted to tomato cultivation in plastic houses, severe disease symptoms, caused by soil borne pathogens, have been found in association with root-knot nematode attacks (Meloidogyne spp.). In many countries to limit damages caused by these plant pathogens and parasites, plant protection is based on chemical treatments (dazomet, oxamyl, fosthiazate and more recently DMDS). In every case new control integrated strategies are required and they must be environmentally safe and economically convenient at the same time. Among these alternatives, the use of new biological active substances, with phyto-stimulating, antimicrobial and nematicidal properties, synthesized by soil microorganisms of the genera Streptomyces, Azotobacter, Pseudomonas and Bacillus can reduce the population level of harmful organisms (plant-parasitic nematodes, phytopathogenous insects, phytopathogenic bacteria and virus) below the threshold of damage. The intensive and repeated use of plastic-houses dramatically increases Meloidogyne spp. attacks with severe yield losses and economic damages. Implementation and application of biological control measures and new cultivation agro-technologies are justified by the expensive chemical treatments which cause soil pollution and a scarce qualitative and security food production. Estimation of phyto-sanitary situation on tomato cultivated in plastic-houses (surface 20 ha) in R. Moldova was carried out during winter-spring period. Some dangerous sedentary endoparasites as Meloidogyne incognita (Kofoid et White) Chitw. and Pratylenchus pratensis (de Man) were extracted from soil samples collected during the survey. In some plastic-houses the root-knot nematode populations exceeding the tolerance limit of tomato plants to the nematode (3.3 eggs and juveniles/cm3 soil). Density of nematode communities including plant parasitic and free-living nematodes varied from 6.75 to 10.25 individuals/cm3 soil. Virus infections (10-15% infected plants) were also observed. Symptoms were mainly due to: a) viral infections by Lycopersicum virus 3 Smith and b) Marmor tabaci var. lycopersicum. Moreover, tomato plants were also affected by Phytophtora infestant (Mont.) de Bary (15-25 %) showing yellow spots and necrosis on leaves and stems (late blight of tomato) and by Fusarium oxysporum Schl. f. sp. lycopersi (5-10 %) with plants showing wilting symptoms. Effectuated monitoring by us served basic element in providing protection integrates methods by decrease phytoparasitic and phytopathologic affections on tomatoes in greenhouse. The researches were made by bilateral project Italy/R. of Moldova "Potential of biological active substances to reduce Meloidogyne harmfulness on horticultural crops in greenhouses". Registry code No 13.820.08.02/ItF. "
New approaches in the control of plant phatogens and phytoparasites (Meloidogyne spp) on tomato in R. Moldova
Sasanelli N
2017
Abstract
"Numerous studies on the interaction between soil borne plant pathogens and phytoparasitic nematodes both on vegetables and fruit trees have been conducted. In the last two decades, in several areas of the R. Moldova, devoted to tomato cultivation in plastic houses, severe disease symptoms, caused by soil borne pathogens, have been found in association with root-knot nematode attacks (Meloidogyne spp.). In many countries to limit damages caused by these plant pathogens and parasites, plant protection is based on chemical treatments (dazomet, oxamyl, fosthiazate and more recently DMDS). In every case new control integrated strategies are required and they must be environmentally safe and economically convenient at the same time. Among these alternatives, the use of new biological active substances, with phyto-stimulating, antimicrobial and nematicidal properties, synthesized by soil microorganisms of the genera Streptomyces, Azotobacter, Pseudomonas and Bacillus can reduce the population level of harmful organisms (plant-parasitic nematodes, phytopathogenous insects, phytopathogenic bacteria and virus) below the threshold of damage. The intensive and repeated use of plastic-houses dramatically increases Meloidogyne spp. attacks with severe yield losses and economic damages. Implementation and application of biological control measures and new cultivation agro-technologies are justified by the expensive chemical treatments which cause soil pollution and a scarce qualitative and security food production. Estimation of phyto-sanitary situation on tomato cultivated in plastic-houses (surface 20 ha) in R. Moldova was carried out during winter-spring period. Some dangerous sedentary endoparasites as Meloidogyne incognita (Kofoid et White) Chitw. and Pratylenchus pratensis (de Man) were extracted from soil samples collected during the survey. In some plastic-houses the root-knot nematode populations exceeding the tolerance limit of tomato plants to the nematode (3.3 eggs and juveniles/cm3 soil). Density of nematode communities including plant parasitic and free-living nematodes varied from 6.75 to 10.25 individuals/cm3 soil. Virus infections (10-15% infected plants) were also observed. Symptoms were mainly due to: a) viral infections by Lycopersicum virus 3 Smith and b) Marmor tabaci var. lycopersicum. Moreover, tomato plants were also affected by Phytophtora infestant (Mont.) de Bary (15-25 %) showing yellow spots and necrosis on leaves and stems (late blight of tomato) and by Fusarium oxysporum Schl. f. sp. lycopersi (5-10 %) with plants showing wilting symptoms. Effectuated monitoring by us served basic element in providing protection integrates methods by decrease phytoparasitic and phytopathologic affections on tomatoes in greenhouse. The researches were made by bilateral project Italy/R. of Moldova "Potential of biological active substances to reduce Meloidogyne harmfulness on horticultural crops in greenhouses". Registry code No 13.820.08.02/ItF. "I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
