Plant Pathology Science

In order to control plant parasitic nematodes, in spite of chemical costs, some may have residue in yield, some kill the natural enemies of nematodes, and many of them may pollute the environment. Based on research carried out by oil, seed kernel extract and powder, and meal of neem, complete bead-tree seed extract and powder, yarrow aerial parts extract and powder, can cause mortality of these onstage juveniles of the root-knot nematode Meloidogyne incognita. The effect of these plants materials on the nematode mortality compared with control and showed statistically significant difference at the level of 1%. Application of these plants materials maybe reduces of chemical pesticides and risks of their using.

Introduction: Root-knot nematodes are one of the most important groups of plant parasitic nematodes in terms of economic damage to agricultural products. Biological control is one of the most environmentally friendly methods for management of nematodes. Material and Methods: The effects of aqueous extracts of jimsonweed  (Datura stramonium), metel (Datura metel) and henbane (Hyoscyamus niger) was evaluated against Meloidogyne javanica on cucumber, under greenhouse condition, in this study. Cucumber plants were inoculated with suspension of eggs and second stage juveniles of nematode. After a week, 1.66% concentration of each plant extract were irrigated in the pots. Plants were harvested after 45 days and some plant growth parameters and nematode reproductive parameters were recorded. Results: The extract of any of the plants did not affect the number of knots on the roots and per gram of the roots. However, number of egg- masses per root and gram of root, treatments including nematodes and extracts had fewer masses compared to treatments without plant extracts. Final population and reproductive factor had also lower values in treatments with plant extract compared to treatments without it. In addition, the plant extracts had no negative effect on the growth factors of the cucumber in the greenhouse. Conclusion: The extracts of Datura stramonium, Datura metel and Hyoscyamus niger reduced the reproduction of nematodes respectively, therefore they can be considered as potential agents in biological control of root-knot nematodes.

Imani S, Moosavi SMR, Zare R, Basirnia T (2021) Optimum substrate and carrier for Purpureocillium lilacinum and its effectiveness against Meloidogyne javanica on tomato. Plant Pathology Science 10(2):50-64.  Doi: 10.2982/PPS.10.2.50.

Introduction: The soil-borne root-knot nematode (Meloidogyne javanica) causes heavy losses in tomato plants every year. Their management by chemical nematicides is difficult, expensive, and may also kill soil beneficial microorganisms, so other safer methods should be used to replace them. Purpureocillium lilacinum is an important biological control agent against root-knot and cyst nematodes. This study was carried out to determine the appropriate substrate and carrier of this fungus and its effect on these nematodes in tomatoes. Material and Methods: P. lilacinum was propagated in vitro on seeds of millet, corn, alfalfa, and clover substrates and their spore production was assessed 10, 20, and 30 days after inoculation. The survival of the fungal spores was then examined in talc, kaolin, and corn cob powder as carriers for 12 months. The effect of the fungus in the mentioned carriers against Meloidogyne javanica on tomato was investigated in the greenhouse by means of a completely randomized design experiment. Results: The highest number of spores in one gram of substrate was produced on millet seed on day 30. The highest number of survived spores was detected in the corncob powder carrier at all 12 months of the experiment. The fungus on corn cob powder was able to control M. javanica to 95% was similar to the nematicide Flopyram. This formulation also had a superior effect in establishing the fungus in the rhizosphere and on roots, suppressing the growth parameters of nematode and increasing plant growth. Conclusion: The fungus reproduced well on millet seeds and could last longer if formulated on corn cobs powder. Therefore, corn cobs powder can be a suitable base to produce an effective powdered product against M. javanica.

Vahabi S, Charehgani H, Abdollahi M, Rezaei R (2021) Response of eight melon cultivars to Meloidogyne javanica. Plant Pathology Science 10(2):65-73.       Doi: 10.2982/PPS.10.2.65.

 Introduction: The Root-knot nematodes (Meloidogyne spp.) are one of the most damaging plant pathogens with a wide host range and cause major losses to agricultural crops. The use of resistant cultivars is considered a safe, economical, and effective method to control these nematodes. Materials and Methods: In the present study, eight melon cultivars namely Ahlam, 105, Tracey, Ronak, Deltagrin, Mac, Holar, and Veno were evaluated for their response to M. javanica. The seeds were planted in 2 kg pots and maintained under natural conditions in Khormuj city, Bushehr province. Seedlings at the four-leaf stage were inoculated with 5000 eggs and second-stage juveniles. The factorial experiment was conducted in a completely randomized design with five replicates. Sixty days after nematode inoculation, the plants were harvested and the plant growth and nematode population indices were evaluated. Results: The results showed that the nematode reproduction factor was significantly lower in Ronak, Deltagrin, and Veno than in the other cultivars. No significant difference was observed in shoot fresh weight of nematode inoculated and non-inoculated plants of Ronak cultivar. Conclusion: Ronak, Delta-green and Veno cultivars are less susceptible to M. javanica.