Guava is an important edible and economic fruit crop distributed worldwide. It is widely infested with root knot nematode, Meloidogyne enterolobii which plays a vital role in causing economic losses. Several management strategies were performed to enhance the health status of guava and also to reduce root knot nematode infestation. Among the different aspects, application of plant growth regulators on guava plants under nursery conditions against root knot nematode, M. enterolobii was performed. The guava plants were treated with Salicylic acid (100 ppm), Jasmonic acid (100 ppm), and Indole 3-Butyric Acid (1000 ppm) alone and in combination of two and three. The result of this study revealed that IBA at 1,000 ppm alone (T3) and combined application of plant growth regulators viz., (T₄) – Salicylic acid (100 ppm) + Jasmonic acid (100 ppm) + Indole 3-Butyric Acid (1,000 ppm) showed reduction in the nematode population and establishment of new roots (compensatory) and tertiary roots. The combined application of PGRs also increased the Plant height, root length, chlorophyll index, photosynthetic rate, transpiration rate, stomatal conductance, and chlorophyll fluorescence. The activity of various enzymes like total phenols, peroxidase, polyphenol oxidase, acid phosphatase, and phenylalanine ammonia lyase were influenced and developed resistance against root knot nematode, M. enterolobii. Under field conditions, application of Pochonia chlamydosporia and Purpureocilium lilacinum reduced the nematode infestation besides increasing the yield attributes of guava plants.

Guava is an important revenue generating crop for small, medium, and commercial guava cultivators all over the world. Nematode infestation is one of the factors that cause declines in fruit production. Researches have proven that the application of plant growth regulators induces the synthesis of defense-related proteins in Guava. IBA is one such plant growth regulator, and its effects on guava plants has not yet been elucidated. Thus, this research is focused on the optimization of IBA concentrations, which results in the induction and production of maximum defense-related proteins to defend against root knot nematode. The present study includes the application of IBA on M. enterolobii-infested experimental guava plants at different concentrations ranging from 100 ppm to 2000 ppm. The synthesis of defense-related proteins is identified with 1000 ppm of IBA. At this concentration, IBA influences the morphological, physiological, and biochemical characteristics and enhances the induction of defense-related proteins in M. enterolobii-infested experimental guava plants. Thus, 1000 ppm of IBA prevents nematode infestation in Lucknow-49 guava plants.

The goal of the current study was to determine how different chemical defoliants and application timing affected defoliation in cotton variety CO 17. The studies were conducted using a split-plot design with three applications at three different times as the main plot and seven defoliants as the subplot. Thidiazuron + Diuron (0.03%) defoliant reduced the gas exchange parameters, photosynthetic rate, transpiration rate and stomatal conductance by reducing plant growth parameters, leaf area, leaf area index, specific leaf weight which significantly increased the defoliation percentage. The negative correlation of cotton growth and gas exchange parameters with defoliation percentage was observed in correlation studies. In conclusion, Thidiazuron + Diuron (0.03%) defoliant was found to be superior in action for improving leaf defoliation and its associated parameters. And also it may be a cost-effective cotton defoliant for aiding the mechanical picking of cotton bolls.

Background: Plant nutrient deficiency is the major challenge in agriculture results in lower crop yield and quality. This may lower the farmer’s income by reducing marketable value. In other hand, eating nutrient dense vegetables is the most cost effective strategy to combat malnutrition. The efficiency of inorganic micronutrients applied into soils is low as they become easily fixed to soil particles. Hence, exogenous application of nutrients is an effective option to enhance plant nutrient use efficiency. Methods: This study was conducted at SRM College of Agricultural Sciences, Chengalpattu, Tamil Nadu during 2022-2023 to alleviate nutrient insufficiency challenges in bhendi variety Senora by using Randomized block design with seven different treatments viz., T1- Control, T2- Nutrient consortia 1 (N + K + B + Fe+ Mn + Zn @ 1% ), T3- Nutrient consortia 2 (N + K + Fe+ Cu + B @ 1%), T4- Nutrient consortia 3 (N + K + Mg + B + Fe + Zn @ 1%), T5- Nutrient consortia 4 (T2 + NAA + SA@ 1%), T6- Nutrient consortia 5 (T3 + NAA + SA @ 1%), T7- Nutrient consortia 6 (T4 + NAA + SA @ 1%), sprayed at 30, 45 and 60 days after sowing. Result: Various physiological, biochemical, yield and quality parameters were measured to evaluate the effects of Nutrient consortia. The results of field experiment strongly improved that the eight biochemical parameters viz., chlorophyll a, chlorophyll b, total chlorophyll content, chlorophyll a/b ratio, chlorophyll stability index, leaf soluble protein, lipid peroxidation by melondialdehyde and proline content. The yield and quality traits such as number of fruits per plant, total fruit yield, total phenolics and total antioxidants activity were significantly increased through application of Nutrient consortia 6 followed by Nutrient consortia 4. So this can be used as yield and quality enhancer formulation of bhendi crops.

Background: Root-knot nematode Meloidogyne enterolobii has emerged as a major constraint to guava (Psidium guajava L.) cultivation in tropical regions, particularly in association with the guava wilt–nematode disease complex. Accurate identification of the nematode species is essential for understanding its distribution and developing effective management strategies. Methods: Soil and root samples were collected from guava orchards affected by wilt symptoms in Tamil Nadu. Adult females were dissected from infected roots and examined for perineal pattern morphology, while second-stage juveniles (J2) were analysed for key morphological and morphometric characters. Molecular identification was performed using species-specific primers with amplification of the ITS and COI regions, followed by sequencing and phylogenetic analysis. Result: The perineal pattern of adult females was oval with a high dorsal arch and absence of lateral lines, characteristic of M. enterolobii. J2 exhibited a hemispherical head, slender tail with a rounded terminus and stylet length ranging from 14.5-16.2 µm. Molecular analysis confirmed the identity of M. enterolobii and the ITS and COI sequences were deposited in GenBank under accession numbers PX667703-PX667705 and PX658232–PX658234, respectively. Phylogenetic analysis showed close clustering of the isolates with reference M. enterolobii sequences.