No abstract

Cotton leaf curl virus disease (CLCuV) is a devastating biotic factor that imposed crop productivity a huge loss. To battle this issue this study was assessed in 2019 for the evaluation of the response of leaf extract of miracle tree (Moringa oleifera L.) and potassium (K) nutrition to mitigate the plague of CLCuV disease in cotton variety CRIS-129. Treatments have consisted of the various K dosses Viz., 0, 100, and 150 kg K2SO4 ha-1, and 3% leaf extract of moringa was sprayed at 30, 60, and 90 days after emergence. Results regarding yield components i-e boll weight (g) and seed index (g) were increased by increasing K application and foliar spray of moringa leaf extract but statistically non-significant (p<0.05). However, seed cotton yield and K contents in cotton leaves were significantly increased with all the treatments. The maximum seed cotton yield (2620 kg ha-1) was achieved with 150 kg K2O ha-1 application and it was increased by about 52% over the control treatment. In the case of incidence % of CLCuV disease, both K nutrition as well as foliar spray played a significant role and CLCuV intensity reduced with increasing rate of K doses and foliar sprays.

Among two methods of Macrophomina phaseolina inoculation used for pathogenicity test, soil infestation method comparatively checked more plant growth of okra plants than seed infestation method. Minimum plant length and weight, as well as seed germination were observed by soil infestation method. Significantly maximum plant mortality and root infection was also occurred in soil infestation method. Seed germination, plant growth, plant mortality and root infection of okra plants were adversely affected with the increasing inoculum levels of M. phaseolina. Seed germination and plant growth were negatively correlated with inoculated pathogen population; whereas, plant mortality and root infection were positively correlated with the inoculum level of M. phaseolina.

Cotton leaf curl disease (CLCuD) caused by Begomovirus(s) is economically important disease of cotton in Pakistan. Management of CLCuD using natural sources of resistance has great significance and is recognized as long term management strategy. In present study, we evaluated resistant potential of 33 cotton genotypes in agro-ecosystem of Sindh, Pakistan within thrice repeated experiments. Observations were taken at interval of 30 days after sowing on incidence and severity of CLCuD under field conditions. Then the disease index was calculated from values of initial observations on incidence and severity of the disease at each time point and finally Area Under the Disease Progress Curve (AUDPC) was calculate for the disease index and presented as semi-quantitative estimate of the disease. Results showed that there was significant difference among AUDPC values of the disease index of tested genotype (LSD=41666, P=0,0000 and LSD=70297, P= 0.0000) during 2018 and 2019, respectively. Significantly highest AUDPC value was recorded in BT.CIM-678 (664109) followed by CRIS-585 (277732) and CRIS-613 (133917) and CRIS-522 (159272) during 2018. The remaining genotypes gave significantly lower AUDPC values. Similar results were obtained during next year of experiment. Therefore, it is concluded that cultivation of BT.CIM-678, CRIS-585, CRIS-613 and CRIS-522 should be avoided in agro-ecosystem of Sindh. Further studies should be conducted for eco-friendly management of the disease.

Six cotton varieties were evaluated at the environmental condition of Sakrand to assess the CLCV disease incidence % and due to its effect reduction in yield and fiber traits. It was confirmed from the present research that cotton leaf curl virus (CLCV) disease incidence generally has adverse effects on cotton crop growth and development, seed cotton yield, and economic traits. The range of disease incidence % was noted from 19.5% (IUB-13) to 56.8% (CIM-602). Due to CLCV disease incidence up to 50% reduction was noted in plant height, bolls plant-1, boll weight, and seed cotton yield. However, fiber quality traits are less decreased as compared yield traits. Therefore, it is always necessary to recommend cotton leaf curl virus disease resistant/tolerant varieties for general cultivation to combat CLCV and also emphasize on proper control of whitefly, as it is a vector for transmitting CLCV disease from one plant to another. There present study was conducted to document Cotton Leaf Curl Virus (CLCV) disease on yield and economic traits of cotton.