Algae are the most important plant growth stimulants due to their high content of minerals, amino acids, vitamins and growth regulators such as auxin, cytokinin and gibberellin. Use of these stimuli in crops can improve rooting, yield, photosynthetic capacity and their resistance to pathogens. Application of algae (mainly seaweeds) against various plant diseases including bacterial, fungal, viral and nematode diseases as well as pests has been proven. Seaweeds are used as a powder or extract mixed with soil, or foliar spray to control of plant diseases. They are usually involved in controlling plant pathogens by inducing plant resistance, antagonistic activity by induced activity of other microorganisms, and enhancing plant growth. In general, seaweeds can be applied as biofertilizers, biostimulators and soil amendments in integrated plant diseases management programs.

Fusarium root and crown rot is one of the most important wheat diseases in the world, which causes a significant reduction in yield. The disease is also common in many wheat production areas in Iran. F. acuminatum, F. avenaceum, F. culmorum, F. solani, F. semitectum, F. equiseti, F. crookwellense, F. lateritium, F. moniliforme, F. oxysporum, F. pseudograminearum, F. sambucinum, F. subglutinans,F. proliferatum, F. longipes, F. nygamai, F. compactum, F. diversisporum, F. fujikuroi, F. javanicum, F. flocciferum and F. tricinctum have been reported from rotten tissues of wheat root and crown in Iran and F. culmorum and F. pseudograminearum are known as the most important disease agents. Disease management methods including crop rotation, removal of diseased plant debris, setting planting date, biological control, seed disinfection with protective fungicides and cultivation of relatively resistant cultivars are described in this article.

Dehghanpour Farashah S (2023) Defense responses by nitric oxide in plant-pathogen interaction. Plant Pathology Science 12(2):130-142.

DL-β-amino-n-butyric acid (BABA) induces resistance in plants against root-knot nematodes (Meloidogyne spp.) by activating natural defense mechanisms. This study evaluated the effect of BABA on the resistance of okra (Abelmoschus esculentus cv. Clemson Spineless) to M. javanica under greenhouse conditions. Seeds were sown in 1 kg plastic pots and maintained at 27 ± 3℃ under a 16:8 hours of light-dark cycle and with daily irrigation. At the four-leaf stage, seedlings were foliar-sprayed with BABA at concentrations of 0 (control), 0.5, 1, and 2 mM. After 24 hours, plants were inoculated with M. javanica at initial population densities of 0 (control), 1, 2, 4, and 8 second-stage juveniles (J2s). Sixty days post-inoculation, plant growth and nematode reproduction indices were assessed. Results showed that higher BABA concentrations significantly improved plants growth and reduced nematodes populations. Plants treated with 2 mM of BABA and inoculated with 8, 4, 2 and 1 J2s showed increases in shoot length by 43.9%, 45.1%, 32.5%, and 32.2%, respectively; shoot fresh weight by 37%, 38.2%, 69%, and 61.5%; and shoot dry weight by 23.5%, 24.5%, 37.4% and 39.7% compared to untreated control. Meanwhile, the nematode reproduction factor decreased by 25.1%, 25.9%, 14.1% and 38.4%, respectively. This study demonstrated that BABA application improves okra growth against M. javanica. Although BABA had no significant effect on the reproduction factor at the highest nematode population level, all concentrations improved plant growth, even under severe nematode pressure. Foliar application of 2 mM BABA effectively enhances okra resistance to M. javanica under greenhouse conditions.