a composition may be prepared comprising a mixture of iprodione and trifloxystrobin in the ratio of about 16 : 1 ( w : w ) in an aqueous solution , by combining suitable amounts of commercial formulations of rovral green gt ™ and compass ™. the said ratio comprises a calculated molar ratio of about 19 . 53 : 1 . the composition may be diluted sufficiently for application on turfgrass at a rate of between 30 and 90 g per 100 m 2 iprodione and between 1 . 9 g and 5 . 7 g per 100 m 2 trifloxystrobin . a composition may be prepared comprising a mixture of iprodione and trifloxystrobin in the ratio of about 3 : 1 ( w : w ) in an aqueous solution , by combining suitable amounts of commercial formulations of rovral green gt ™ and compass ™. the said ratio comprises a calculated molar ratio of about 3 . 93 : 1 . the composition may be diluted sufficiently for application on turfgrass at a rate of between 4 . 92 and 14 . 76 g per 100 m 2 iprodione and between 1 . 55 g and 4 . 65 g per 100 m 2 trifloxystrobin . the composition may be applied to turfgrass plots in different geographic zones in canada , including the region subject to more than 150 days of substantially continuous snow cover , and regions subject to between 90 and 120 days of substantially continuous snow cover . chemical treatments were applied in the late fall at the rate described above , and assessments of snow plots were taken in the spring , after snow cover had melted off of the trial plots . fig1 through 6 illustrate test results for three snow mould funguses , t . ishikariensis , m . nivale , and t . incarnate , on plots covered with snow for approximately 100 days ( fig1 & amp ; 2 ), approximately 120 days ( fig5 & amp ; 6 ), or trial tarped for 4 months to simulate snow cover . plots covered with snow had natural snow mould infection , while tarped plots were inoculated with the fungus indicated . the graphs illustrate the percentage of snow mould infection on the tested plot , for different application strengths ( in g per 100 m 2 ) of compass ™, rovral green gt ™ (“ rg gt ”), alone and in combination . it was found that a tank mix for application of 250 ml rovral green gt ™ ( per 100 m 2 ) and 7 . 6 g of compass ™ ( per 100 m 2 ) provided approximately 99 % control of t . incarnate , and about 92 % control of t . ishikariensis , and 97 % control of m . nivale . the tank mixtures described herein thus lead to more inhibition than similar amounts applied separately of the above components to different plots . thus , there exists synergy in the mixture described above , thereby permitting greater inhibition with a lower dosage rate . in the examples herein , the compass formulation comprises 50 % active substance . further , in several of the above examples tarped and untarped fields were tested with the tarped fields requiring no greater amount of the composition to achieve effective inhibition . a trial was conducted in a region in canada having a substantially continuous snow cover duration of more than 150 days , with relatively high disease pressure . the mixture of rovral green gt ™ at 250 ml and compass ™ at 7 . 6 g ( per 100 m 2 ) was applied prior to snow cover , and an assessment conducted after snow melt . two applications of the mixture and controls were applied about 10 days apart . after snow melt , the percentage disease spread of t . ishikariensis and m . nivale were detected . the rovral green gt ™ and compass ™ mixture resulted in about 25 % disease cover , while rovral green gt ™ at the higher dose rate of 360 ml per 100 m 2 ( recommended treatment level ) resulted in 71 . 25 % disease cover , while compass ™ at 7 . 6 g per 100 m 2 resulted in 78 . 75 % disease cover . three different turfgrass plots infected with dollar spot mould ( s . homeocarpa ) in three different locations was treated with one of 3 . 1 g of compass ™ (“ comp ”)/ 100 m 2 , 4 . 6 g of compass ™/ 100 m 2 , 62 ml of rovral green gt ™ (“ gt ”) or a combination of 3 . 1 g / 41 ml compass ™/ rovral green gt ™/ 100 m 2 on either 14 , 21 or 20 - 21 day intervals . fig7 illustrates the percentage of s . homeocarpa inhibition as compared to an untreated test plot , for each of the different application strengths ( in g per 100 m 2 ) of compass ™, rovral green gt ™, alone and in combination . fungicidal compositions according to the invention may be supplied in a concentrated liquid , powder or granular form or any other form commonly used in the agricultural industry . the fungicidal composition may also be supplied in combination as a pre - mix to be diluted to the correct concentration or supplied as individual components to be combined in a tank mixture . preferably the compositions are diluted with water but other suitable diluents are possible . other active or inactive constituents may also be added . although the tested embodiments relate to tank mixtures , improved results may also be obtained by separately applying the two active components in close time proximity . although this invention has been described in terms of a preferred embodiment , other embodiments that are apparent to those of ordinary skill in the art are also within the scope of this invention . accordingly , the scope of the invention is limited only in scope by the following claims and functional equivalents thereof .
a composition for treating fungus infection of turfgrass , such as snow mould infection , comprises a mixture of fungicidally effective amounts of formulae 1 and 2 : and in particular mixtures of iprodione and trifloxystrobin . a method for treating snow moulds comprises applying the mixture before the onset of continuous snow cover , in at least one application .