Root-knot nematodes (RKN) are globally distributed and highly pathogenic. By determining the threshold at which damage occurs, we can create effective measures to protect plants from nematodes. In our study, we investigated the impact of ten initial population densities (Pi-log series) of M. javanica, i.e., 0, 2.38, 2.68, 2.98, 3.28, 3.58, 3.88, 4.18, 4.48 and 4.78 juveniles (J2) g(-1) soil on tomato cv. S22 plants in pots. The graphical estimation of yield losses caused by RKN was calculated using Seinhorst's yield loss model based on the relationship between the RKN population and damage to tomato plants. The relationship between initial nematode population density (Pi) and plant yield was analyzed using Seinhorst's model, where T is the tolerance limit, m is the minimum yield, and z is a constant describing yield decline. This allowed us to determine the threshold at which nematode infestation significantly reduces tomato growth. Seinhorst's model, y = m + (1-m) 0.95(Pi/T-1) for Pi > T; y = 1 for Pi <= T for RKN, was fitted to the data of shoot length and fresh weight of infected and uninoculated control plants to estimate the damage threshold level. The impact of M. javanica on plant physiological parameters, including chlorophyll content, carotenoid and nitrate reductase activity, root-gall formation, and disease incidence, was also determined in this study. The tolerance limits for relative tomato shoot length and fresh weight were 3.34 J2 of M. javanica g(-1) soil. The minimum relative values (y(m)) for shoot length and fresh weights were 0.39 and 0.42, respectively. We found that the damage threshold level was between 3.28 and 3.58. The root galls index, nematode population and reproduction factors were 3.75, 113 and 29.42, respectively, at an initial population density (Pi) of 3.58 J2 g(-1) soil. The chlorophyll (0.43 mg g(-1)), carotenoids (0.06 mg g(-1)) and nitrate reductase activity (0.21 mu mol min(-1) g(-1)). Our study highlights the importance of the accurate estimation of damage thresholds, which can guide timely and effective nematode management strategies.

With an increase in global demand for food without unwanted environmental issues stresses a need for sustainable agriculture. Up till now, conventional agricultural methods focused on obtaining great crop yields from the use of chemical fertilizers but overlooked the hazardous concerns that are leading to soil depletion. These chemical fertilizers adversely affect soil structure, decrease fertility, damage soil flora, and lead to soil erosion. In this scenario, understanding the natural mechanisms of plant-microbe interactions in the rhizospheric environment can potentially lead a way towards eco-friendly agriculture, as the plant associating bacteria prompting phytostimulation can be the key players in unlocking sustainable alternative for conventional fertilizers. Plant growth-promoting bacteria (PGPB) are a distinct class of soil microorganisms that promote plant growth and yields by enhancing nutrient delivery and shielding the plants against diseases. N fixing bacteria such as Rhizobium and Azotobacter, for instance, fix atmospheric nitrogen into a usable form for plants, Pseudomonas and Bacillus induce root and shoot elongation by synthesizing phytohormones. These bacteria also provide protection to plants by synthesizing antimicrobial substances and increasing the competitive nature of the rhizosphere. Bacteria like Azospirillum, Enterobacter, and Flavobacterium also stimulate plant growth by producing phytohormones under specific envirnmental conditions. Utilization of PGPB as bio-stimulants in agriculture is a promising method for sustainable agriculture dependence on chemical fertilizers and maintaining soil health. This approach would play an important role in sustaining a balanced ecosystem along with increasing agricultural productivity.

The EFSA Panel on Plant Health performed a pest categorisation of Dendrolimus punctatus (Lepidoptera: Lasiocampidae), following a commodity risk assessment of bonsai Pinus parviflora grafted onto P. thunbergii from China, in which D. punctatus was identified as a pest of possible concern to the European Union (EU). D. punctatus, also known as the Masson pine caterpillar, is present in China, Taiwan, Vietnam, India and has recently spread to Japanese islands close to Taiwan. Larval feeding on the needles of Pinus elliottii, P. luchuensis, P. massoniana, P. merkusii and P. tabulaeformis causes important damage. D. punctatus larvae can also feed on P. armandii, P. echinata, P. latteri, P. parviflora, P. sylvestris var. mongolica, P. taeda, P. taiwanensis and P. thunbergii, but full development on these hosts is uncertain. The pest has three to five generations per year; winter is spent as larvae on branch tips, on tree trunks and in the soil. The females lay egg clusters on pine needles. Pupation occurs in cocoons attached to branches or needles. D. punctatus could enter the EU either as eggs, larvae or pupae in the foliage of plants for planting or cut branches, as larvae on wood with bark or as overwintering larvae in branches, crevices in the bark or in the litter of potted plants. However, Annex VI of 2019/2072 prohibits the introduction of D. punctatus hosts (Pinus spp.) from countries and areas where the pest occurs. There are climate zones where the pest occurs in Asia that also occur in the EU, though they are limited, which constitutes an uncertainty regarding establishment. The pest's main hosts are not grown in the EU. However, the fact that it attacks the North American Pinus echinata, P. elliottii and P. taeda in its Asian native area suggests a potential capacity to shift to pine species occurring in the EU territory. D. punctatus satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. Whether the Pinus commonly found in Europe could act as hosts is unknown but is fundamental, affecting the criteria of establishment and magnitude of impact.