Sensitivity of Colletotrichum acutatum Isolates to Selected Fungicides

Abstract

Laboratory tests of six isolates of the pathogen Colletotrichum acutatum from diff erent host plants demonstrated the varying sensitivity of pathogen with regard to mycelium growth and conidial germination a er treatment with seven fungicides containing various active ingredients. None of the evaluated isolates was tolerant to the selected active ingredients in the fungicides. In tests of mycelium growth sensitivity, isolates from lupin and strawberry were most frequently identifi ed as the most sensitive of all evaluated fungicides. The saffl ower isolate, on the other hand, most frequently exhibited the lowest reaction to fungicides. Diff erences in conidial germination of individual isolates were not detected in fungicides with the active ingredients dithianon, folpet and mancozeb, for which inhibition reached 100% in almost all isolates. The most signifi cant diff erences in sensitivity among individual isolates were recorded in fungicides with the active ingredients azoxystrobin and metiram. In the case of the fungicide with active ingredient azoxystrobin, the highest inhibitory eff ect was achieved in the saffl ower isolate and the lowest in the white lupin isolate. A er treatment with the fungicide with active ingredient metiram, the lowest germination rate was recorded in isolates from saffl ower and strawberry and the highest in isolates from hypericum and lupin.

Available Strategies for the Management of Andean Lupin Anthracnose

“…Seed treatment with fungicides reduces transmission of the pathogen from seed coat to seedling, but it does not provide complete control [ 109 ]. The synthetic fungicides generally recommended for controlling anthracnose disease are based on copper compounds, dithiocarbamates, benzimidazole and triazole compounds, manganese ethylenebisdithiocarbamate (Maneb) [ 109 , 110 , 111 ], and carbendazim [ 110 ], although the use of fungicides has been found ineffective under severe disease outbreak [ 109 ]. Newer chemicals like strobilurins (e.g., azoxystrobin, pyraclostrobin) have also been used for lupin anthracnose management [ 38 , 109 , 112 ].…”

“…Farmers should take prevailing environmental conditions into consideration in their choice of fungicides. Rotation of two or more different classes of fungicides is highly recommended for increasing the chance of better protection against the disease in the fields [ 111 , 112 , 113 , 114 ]. Applications of Boscalid + Piraclostrobin or Azoxystrobin + Difeconazole significantly reduced the severity and infection in seed and significantly increased grain production [ 38 ].…”

“…Effective control through the use of chemical fungicides is possible by timely application during the critical period favorable for the onset of the disease [ 109 , 110 , 111 , 112 , 113 ]. Generally, fungicides should be applied for seed disinfection [ 109 ], at young seedling emergence, including early flowering or full bloom, and early pod formation to restrict the entry of the pathogen to the plant system [ 109 , 110 , 111 , 112 , 113 ].…”

“…The first critical step is to reduce infection in seed ( Figure 5 ) by using dry heat [ 45 ], UV-C radiation [ 51 ], or UV-B radiation [ 56 ]. Further protection can be added by combining physic treatments with other techniques, such as biological [ 57 , 58 , 59 , 94 , 98 ] or chemical control [ 38 , 109 , 110 , 111 , 112 , 113 ]. If one of the physic treatments of seed is used for high rainfall regions, it should be supplemented with foliar sprays to suppress pathogen dispersion in the field and subsequent infections.…”