Management of Early Blight disease of Tomato caused by Alternaria solani Ellis and Martin Jones and Grout

Abstract

Early blight caused by Alternaria solani (Ellis andMartin) Jones and Grout is a major newlinedevastating disease of Tomato causing significant reduction of fruit yield. Considering the newlineeconomic importance of the disease present investigation has been come out. The systematic newlineinvestigation revealed that Tomato was observed to be infected with early blight at all newlinelocations surveyed. The disease intensity varied from 26.90 to 42.84 percent and 20.55 to newline45.29 percent during Rabi, 2020-21 and Rabi, 2021-22 cropping season respectively. newlineThe pathogen was isolated from infected leaves and identified on the basis of newlinemorphological characters after microscopic examination of the culture on PDA medium as newlineAlternaria solani. Mycelium was dark brown, Conidiophores were brown to olivaceous newlinebrown, conidia having two to six transverse and one to three longitudinal septation with long newlinebeak. The dimensions of conidia were ranged from 83.4 - 233.0 × 17.5 - 36.4 µm. newlineThe crop sown on October 23rd recorded lowest mean percent disease intensity newline(26.42%) and maximum mean fruit yield (16.04 t/ha). Crop sown on December 11th recorded newlinehighest mean percent disease intensity (49.98 %) and lowest mean fruit yield (11.60 t/ha). newlineLate sowing favoured development of early blight of tomato. The temperature ranged from newline10.79 to 29.830C, relative humidity ranged from 52.56 - 91.22%, rainfall ranged from 0.20 to newline0.24 mm and sunshine hr. ranged from 06.83-7.07 hrs. (Rabi, 2020-21). Whereas the newlinetemperature ranged from 11.99 to 28.010 C, relative humidity ranged from 55.49- 93.43 newlinepercent , total rainfall ranged from 0.48 to 0.58 mm and sunshine hour ranged from 06.32- newline6.48 hrs. (Rabi, 2021-22) apparently favoured the disease development. Disease severity was newlineprogressing at linear rate throughout the plant growth and it was significant and positively newlinecorrelated with maximum temperature, minimum temperature and sun shine hr., negatively newlinecorrelated with morning relative humidity, evening relative humidity and rainfall during both newlinethe year (Rabi, 2020-21 and Rabi, 2021-22). The correlation between weather parameter and newlinefruit yield of tomato was significant and negatively correlated with maximum temperature, newlineminimum temperature, and sun shine hrs., positively correlated with morning relative newlinehumidity, evening relative humidity and rainfall during both the year (Rabi, 2020-21 and newlineRabi, 2021-22). newlineIn-vitro evaluation of plants extracts against Alternaria solani pathogen revealed that newlineleaf extract of Tulsi (Ocimum sanctum) recorded maximum inhibition of mycelial growth newline(65.00%) followed by leaf extract of Neem (Azadirachta indica) which recorded 55.00 newlinepercent mycelial growth inhibition at 10 percent concentrations. At 15 percent concentration newlineleaf extract of Datura (Datura stramonium) recorded maximum inhibition of mycelial growth newline(68.33%) followed by leaf extract of Tulsi (Ocimum sanctum) recorded 65.37 percent newlinemycelial growth inhibition. newlineIn-vitro bioassay of bio-agents by dual culture technique showed that T. harzianum newlineinhibited maximum mycelial growth i.e. 64.72 percent followed by T. viride (60.83%) against newlineA. solani. newlineIn-vitro evaluation of four systemic, three combi and three non systemic fungicides newlineagainst A.solani pathogen revealed that the systemic fungicides viz. Hexaconazole 5EC newline(Contaf Plus) and Propiconazole 25EC (Tilt) at 500 ppm, 750 ppm, 1000 ppm and combi newlinefungicide ie Zineb 68% + Hexaconazole 4% (Avtar) at 1000 ppm, 1500 ppm and 2000 ppm newlineinhibited 100 percent mycelial growth of A.solani at all concentrated tested. newlineThree selected fungicides (Indofil M-45, Saaf, Contaf Plus) one bio agent (T. newlineharzianum), one plan plant extract (Datura leaf extract) alone and their different combination newlineevaluated against early blight under field conditions and observed that the treatment newlinecombination i.e. T. harzianum at5g/kg seeds, when used as seed treatment + One foliar newlinespray of Datura leaf extract at15% + Two foliar spray of Indofil M-45 at 0.25% recorded newlineminimum mean disease intensity (13.94 %), maximum mean percent plant disease control newline(65.91%) and maximum mean fruit yield (17.31 t/ha) as per pooled data Rabi,2020-21 and newlineRabi, 2021-22. newlineOut of fifteen varieties screened against early blight of tomato, the varieties, Swarn newlineLalima, Swarn Naveen, Swarn Sampada, Swarn Vijaya and Swarn Anmol showed newlinemoderately resistant (MR) reaction against the disease. newlineKey words: Alternaria solani, bio agent, fungicide, plant extract, percent disease intensity, newlinetomato, weather factors, varieties and yiel newline