Plant-parasitic nematodes are one of the economically most important pathogens, and how rising soil temperatures due to climate change impact their ability to damage crops is poorly understood. The current study was conducted to evaluate the reproduction biology (reproduction and virulence) of Rotylenchulus reniformis and Meloidogyne floridensis on tomato at soil temperatures of 26 °C (control), 32 °C, 34 °C, and 36 °C. The reproduction and virulence of both nematode species were differentially impacted by soil temperature. Relative to the control, the increase in reproduction of R. reniformis ranged from 20% to 116% while that of M. floridensis ranged from 22% to 133%. The greatest reproduction of R. reniformis was observed at 34 °C while that of M. floridensis was observed at 32 °C. Across all temperatures, reproduction of M. floridensis was 2.9 to 7.8 times greater than the reproduction of R. reniformis, suggesting that the former nematode species has a greater fecundity. The rates of change in reproduction relative to the controls were greater in M. floridensis than in R. reniformis, indicating that the latter nematode species is more resilient to changes in soil temperature. The virulence of both nematode species increased numerically or significantly at 32 °C and 36 °C, but not at 34 °C. The greatest virulence of both nematode species was observed at 36 °C at which 57% and 60% root biomass was lost to R. reniformis and M. floridensis, respectively, compared to the root biomass of uninoculated plants at that temperature. The results of the current study suggested that crop damage by nematodes will likely increase as global soil temperature continues to increase.

Two peach rootstocks (‘Guardian’ and ‘MP-29’) and ten winter cover crops (rye, wheat, barley, triticale, oat, Austrian winter pea, crimson clover, balansa clover, hairy vetch, and daikon radish) were evaluated in a greenhouse environment to determine their suitability to host ring nematode, Mesocriconema xenoplax. Each crop was inoculated with 500 ring nematodes, and the experiments were terminated 60 days after inoculation. The reproduction factor (ratio of final and initial nematode population) ranged from 0 to 13.8, indicating the crops greatly varied in their host suitability to ring nematode. ‘Guardian’ has been known to tolerate ring nematode; however, results from the current study suggest the tolerance statement is anecdotal. Another peach rootstock, ‘MP-29’, was also a good host for ring nematode, suggesting an urgency to develop ring nematode-resistant peach rootstocks. Wheat supported the least to no nematode reproduction while pea supported the greatest reproduction. The rest of the cover crops were poor to good hosts to ring nematodes. Although planting cover crops in peach orchards is not common, employing non or poor host crops can help suppress nematodes in addition to having soil health benefits. Furthermore, peach breeding programs should focus on finding and introgressing ring nematode resistance in commercial rootstocks.

Greenhouse experiments were conducted to determine the host suitability of ten summer cover crops and two peach rootstocks to Meloidogyne floridensis by inoculating them with 10,000 M. floridensis eggs. Brown top millet and sunn hemp were nonhosts as they did not support nematode reproduction. Buckwheat, cowpea, pearl millet, Japanese millet, and sunflower supported more than 25,000 eggs/pot, which indicated that these crops are good hosts to M. floridensis. The crops that supported poor nematode reproduction were sesame, grain sorghum, and sorghum-sudangrass, with their reproduction ranging from 219 to 7,750 eggs/pot. In addition to having many galls on the roots, the peach rootstock Guardian had 10,100 eggs on the roots and 450 second-stage juveniles in the pot, which indicated that ‘Guardian’ is a good host to M. floridensis. Although the nematode reproduction on MP-29 rootstock was relatively lower, the presence of many large galls on the roots indicates MP-29 is susceptible to M. floridensis. Results from the current study suggest that the employment of nonhost cover crops and poor-host rootstocks could aid in effective nematode management programs for peaches.

Management of the reniform nematode ( Rotylenchulus reniformis Linford and Oliveira) in upland cotton ( Gossypium hirsutum L.) continues to be a challenge primarily due to inconsistent performance of resistant genotypes. We hypothesize that diversity in reproduction and virulence in R. reniformis has contributed to the inconsistent performance of resistant cotton genotypes. R. reniformis isolates from Tennessee (TN), Alabama (AL), Mississippi (MS), Texas (TX), Louisiana (LA), Arkansas (AR), Florida (FL), South Carolina (SC), and Georgia (GA) were assessed for their reproduction and virulence on a resistant cultivar, DP 2141NR B3XF, and a susceptible cultivar, DP 2317 B3TXF. The AR isolate had the greatest reproduction factor (Rf) of 19.7, while the AL isolate had the lowest Rf of 3.3. Rfs of other isolates were intermediate. Up to 85% of reproductions were suppressed by the resistant cultivar relative to the susceptible cultivar. While plants inoculated with nematodes had lower root biomass than the noninoculated control, the degree of root biomass reduction varied by isolate, suggesting differing levels of virulence among R. reniformis isolates. The AR isolate reproduced the most and was the most virulent. The AL isolate reproduced the least and was less virulent. The AR, MS, TN, and LA isolates were the top four reproducing isolates, probably indicating a greater suitability of the Delta region for nematode reproduction. The correlation analysis indicated that up to 85% of variation in plant biomass was explained by nematode reproduction. These results suggest that resistance breeding programs in cotton must consider the diversity in R. reniformis .

A study was carried out in the Humla district during 2078 B.S. to examine the local cropping pattern, production status, and indigenous practices of crops. To gather information, a semi-structured questionnaire was used to survey 52 households, and two focus group discussions were conducted. The study found that the major indigenous crops were summer crops that were sowed in the months of Baisakh and Jestha and harvested in Ashoj and Kartik. These crops required less water. On the other hand, winter season crops such as naked barley and wheat (pabai) required more than seven months for harvesting. Beans, buckwheat, potato, and finger millet were the major crops produced in the study area. Beans, buckwheat, and barley were cultivated by a higher number of households, while buckwheat, potato, and beans had high crop production. The majority of farmers practices a two-year crop rotation. Additionally, the study found that socio-economic factors such as gender, farmer’s age, caste, family size, and total crop production had a significant relation on maintaining on-farm crop diversity. The study concluded that local farmers in Humla district continue to rely on traditional practices for crop management, which are well-suited to the local agro-climatic conditions. However, it is necessary to give greater emphasis to increasing cropping intensity through the introduction of new technology and innovation, suitable crop management methods, and the protection of indigenous crops to enhance food security and agricultural sustainability in the region.

Karnali province, with an HDI of 0.53, cannot compete with other provinces on production and productivity due to mountainous terrains. It is rich in agrobiodiverisy and indigenous knowledge systems shaped by diverse climate, culture and food systems which allow to practice agro-ecology based production systems. The promotion of local, safe and healthy food systems through the adoption of ecological practices is the only option to get better return from agricultural production and improve the food and nutrition insecurity of the province. The study aims to identify the climate resilient agro-ecological practices practiced by the people and how the socio-economic condition of the people affects the adoption of such technologies and practices. Data collected through household surveys, Focus Group Discussion (FGD) and Key Informant Interviews (KII) from the Karnali river basin districts were analyzed using descriptive and inferential statistics. Results showed that eighteen different climate resilient agro-ecological practices categorized under six different headings such as cropping/planting method, resilient seed/breed, disease and pest management, water management, carbon/nutrient management and farmer’s risk reduction were found being practiced by the farmers. The highest number of climate resilient ecological practices were found being practiced in pulses (11), followed by cereals, vegetables, and oil crops (10). Women were more trained in agro-ecological farming than men. Each variable of the socio-economic condition except caste and income showed a significant relationship with the adoption of climate resilient agro-ecological practices. Awareness along with participatory engagement of the various stakeholders in demonstrating the practices and generating evidence can be suggested to convince them to the promotion of agro-ecology.