Unraveling the enigma of root-knot nematodes: from origins to advanced management strategies in agriculture.

MAIN CONCLUSION: Integrated management strategies, including novel nematicides and resilient cultivars, offer sustainable solutions to combat root-knot nematodes, crucial for safeguarding global agriculture against persistent threats. Root-knot nematodes (RKN) pose a significant threat to a diverse range of host plants, with their obligatory endoparasitic nature leading to substantial agricultural losses. RKN spend much of their lives inside or in contact by secreting plant cell wall-modifying enzymes resulting in the giant cell development for establishing host-parasite relationships. Additionally, inflicting physical harm to host plants, RKN also contributes to disease complexes creation with fungi and bacteria. This review comprehensively explores the origin, history, distribution, and physiological races of RKN, emphasizing their economic impact on plants through gall formation. Management strategies, ranging from cultural and physical to biological and chemical controls, along with resistance mechanisms and marker-assisted selection, are explored. While recognizing the limitations of traditional nematicides, recent breakthroughs in non-fumigant alternatives like fluensulfone, spirotetramat, and fluopyram offer promising avenues for sustainable RKN management. Despite the success of resistance mechanisms like the Mi gene, challenges persist, prompting the need for integrative approaches to tackle Mi-virulent isolates. In conclusion, the review stresses the importance of innovative and resilient control measures for sustainable agriculture, emphasizing ongoing research to address evolving challenges posed by RKN. The integration of botanicals, resistant cultivars, and biological controls, alongside advancements in non-fumigant nematicides, contributes novel insights to the field, laying the ground work for future research directions to ensure the long-term sustainability of agriculture in the face of persistent RKN threats.

Impact of fermented organic formulations combined with inorganic fertilizers on broccoli (Brassica oleracea L. var. italica Plenck) cv. Palam Samridhi.

A two-year field experiment (2018-19 and 2019-20) was laid out in a randomized complete block design (RCBD) with a spacing of 60 × 45 cm involving three replications with ten treatments having cow manurial amendments along with integrated nutrient management in a plot size of 3.0 m × 1.8 m. The effect of the integration of cow manurial amendments and mineral fertilizers on soil fertility, nutrient uptake, yield, and economics of broccoli was studied. The experiment was laid out during the rabi season in the mid-hills of Himachal Pradesh. T8 [90% RDN (112.5 N: 67.5 P: 46.8 K kg/ha) + 5% jeevamrit (1.5 l/m2) + 5% jeevamrit foliar spray] obtained the greatest organic carbon (20.93 g kg-1), available N (375.13 kg ha-1), P (48.46 kg ha-1), K (260.53 kg ha-1) in the soil as well as more uptake of N (60.58 kg ha-1), P (7.25 kg ha-1) and K (37.88 g ha-1) by the plants. Further, this treatment obtained the greatest value for yield (186.77 q ha-1 and 12.44 kg plot-1), net income (₹ 245840) and cost-benefit ratio (1.93). Outcomes of this investigation suggested that combined usage of cow manure, jeevamrit, beejamrit, and ghanjeevamrit with inorganic fertilizers proved to be useful for enhancing soil health, increasing nutrient uptake, and ensuring sustainable production of broccoli.

Effect of prey density on the performance of Eupeodes corollae and its predation rate against the cabbage aphid, Brevicorynae brassicae (L.).

Eupeodes corollae (F.) (Diptera: Syrphidae) is the most abundant syrphid fly which is distributed worldwide and is the sole predator of aphids. Therefore, the present study was conducted to evaluate the predation rate and functional response of E. corollae against the cabbage aphid, Brevicoryne brassicae (L.). The experiment was carried out under laboratory conditions at 25 ± 2°C with 60-70% relative humidity. The results revealed that age-specific net predation rate (qx) increased after the 4th day and a peak was recorded on the 10th day of pivotal age in the third larval instar. The stable host kill rate and finite host kill rate of E. corollae were 18.63 and 21.07, respectively, against the B. brassicae and predicted that a mean of 20.78 aphids was needed for E. corollae to produce one offspring. A negative linear coefficient (P < 0) indicated the type II functional response for all larval instars of E. corollae against the B. brassicae. At higher prey density, the prey consumption was significantly at par with second and third instar larvae of E. corollae as the prey consumption was increased with increasing the prey density, which then decreased after attaining the upper asymptote (76.40 and 81.40% consumption, respectively). The Roger's predator random equation for type II functional response was fitted to estimate attack rate (a) and handling time (Th). The maximum prey consumption was recorded for third instar of E. corollae with a higher attack rate (0.336 h-1) and lower handling time (0.514 h) against B. brassicae, followed by the second and first instar. Thus, it is concluded that the third larval instar of E. corollae was the voracious feeder and used as an efficient biocontrol agent in the IPM programme.