Fungicides Screening And Field Control To Marssonina Leaf Blotch, Moldy Core And Core Rot In Apple

The disease Marssonina leaf blotch and Moldy Core and Core rot on apple are serious inrecent years. The two kinds of diseases can impact on output and quality of apple seriously.For the effective prevention and control of the disease, this paper studies the different kinds offungicides against to the two diseases indoor inhibition effect and field control effect.1. In order to extend the period of validity of the test mixture in controlling the disease ofMarssonina leaf blotch on apple, the traditional Bordeaux mixture was improved. In thetraditional preparation method of Bordeaux mixture (1:2:200) basis, adding differentconcentration of white latex solution, and did indoor and field study, the results showed that,the Bordeaux mixture rain erosion resistant time has a very good role extension when whitelatex in high concentration (2.0%); the duration extension is91.67%of the ordinary Bordeauxfield duration nearly two times, can reduce the times of spraying nearly half. But the whitelatex concentration increased improved mixture viscosity, not conductive in medicamentspraying.2. This study investigated seven fungicides in controlling the disease in vitro and in field.The inhibition of43%Tebuconazole SC,50%Kresoxim-methyl WG,40%MyclobutanilWG,30%Hexaconazole SC,10%Difenoconazole SC,25%Propiconazole EC andSMT·Tebuconazole SC on conidia germination was97.17%,97.04%,72.57%,60.88%,55.34%,84.45%and90.87%;84.71%,96.20%,70.77%,83.92%,75.22%,88.21%and71.79%on mycelium dry weight.80%Bordeaux mixture WP and seven fungicides spraying alone were studied as well as80%Bordeaux mixture WP mixed with four fungicides.80%Bordeaux mixture WP andwhose mixture with43%Tebuconazole SC,50%Kresoxim-methyl WG,25%PropiconazoleEC and SMT·Tebuconazole SC was sprayed in July10th, control effect was1.67%,89.71%,88.73%,77.15%and80.19%;41.81%,72.89%,70.57%,68.98%and65.57%control effectwas showed when sprayed when rate of diseased leaves was about5%.43%Tebuconazole SC,50%Kresoxim-methyl WG,40%Myclobutanil WG,30%Hexaconazole SC,10%Difenoconazole SC,25%Propiconazole EC and SMT·Tebuconazole SC was sprayed continual tow times (every7days) at rate of diseased leaves was about15%,control effect was81.37%,82.85%,58.55%,74.16%,52.92%,76.05%and78.17%. controleffect was81.37%,82.85%,74.16%,76.05%and78.17%; however, control effect40%Myclobutanil WG and10%Difenoconazole SC was just58.55%and52.92%. But, failed tocontrol the disease when rate of diseased leaves was about30%, control effect of each ofthem was48.35%,49.64%,23.60%,28.97%,36.66%,37.96%and43.81%.Therefore, we can spray80%Bordeaux mixture WP tow times (every20days) beforethe trees are infected;80%Bordeaux mixture WP mixed with43%Tebuconazole SC,50%Kresoxim-methyl WG,25%Propiconazole EC and SMT·Tebuconazole SC can be used towtimes (every20days) due to a minor illness; however，the disease expend fast when the rateof diseased leaves resched about15%(late-July to early-August), we should spray43%Tebuconazole SC,50%Kresoxim-methyl WG,30%Hexaconazole SC,25%PropiconazoleEC and SMT·Tebuconazole SC tow times(every7days) to control it effectively.3. The study aimed to screen the fungicides had optimum antibacterial effects on moldy-core and core rot disease in apple. The eight kinds of pathogenetic fungus that lead to moldy-core and core rot disease in apple were treated separately with three kinds of fungicidesindoors. The results showed that3%polyoxin WP had more than90%antibacterial rateagainst to the tested fungus (Alternaria alternate, A. arborescens, A. tenuissima,Cladosporium cladosprioides, Trichothecium roseum and Phoma glomerata).1.5%benziothiazolinone EW had more than90%antibacterial rate against to Alternaria alternate,A. arborescens, T. roseum and C. cladosprioides.4%TF120AS only had strong action to T.roseum, with94.2%inhibition rate. The inhibition rate of polyoxin to the five kinds of fungusreached more than80%in the concentration30g/ml, but failed to inhibit the F. proliferatumwhich inhibition rate was only6.6%; In addition to the F. proliferatum, the EC50of polyoxinagainst to the other seven kinds of tested fungus were less than20g/ml. Under theconcentration of300g/ml, benziothiazolinone had perfect action to the tested fungus, theinhibition rate to A. alternata, A. tenuissima, A. arborescens, C. cladosproioides and T.roseum reached more than80%. When tested under the concentration of200g/ml, TF120showed good inhibitory effect to T. roseum.25%JS399-19SC showed perfect inhibitoryeffect to Fusarium equiseti, F. proliferatum, F. graminearum and F. tricinctum.