Potential Impact of Populations Drift on Botrytis Occurrence and Resistance to Multi- and Single-Site Fungicides in Florida Southern Highbush Blueberry Fields.

Incidence of blossom blight and Botrytis fruit rot (BFR), caused by Botrytis cinerea, on two southern highbush blueberry cultivars was evaluated in several blueberry fields grown in the vicinity (BB-Str(+)) or not (BB-Str(-)) of strawberry fields in central Florida. Blossom blight and BFR incidence were higher in BB-Str(+) fields in 2014 and significantly higher in 2015 compared to BB-Str(-) fields. In total, 613 B. cinerea isolates (i.e., 181 and 432 isolates from BB-Str(-) and BB-Str(+) fields, respectively) were collected. The isolates were evaluated for sensitivity to eight single-site and one multisite fungicides using a spore germination and a germ tube elongation assay. Overall, 5, 15, 24, 28, 54, and 93% of isolates collected from BB-Str(-) were resistant to penthiopyrad, cyprodinil, boscalid, fenhexamid, pyraclostrobin, and thiophanate-methyl, respectively. Respective resistance frequencies in BB-Str(+) isolates were 10, 30, 65, 66, 89, and 99%. Resistance frequencies for all fungicides were always higher in BB-Str(+) fields compared to BB-Str(-) fields. Isolates exhibiting resistance to six or five fungicides simultaneously were predominant (50 to 70%) in blueberry fields regardless if they were grown in the vicinity of strawberry fields or not. Among 308 and 305 B. cinerea isolates tested in 2014 and 2015, 41.8 and 47.1%, respectively, showed reduced sensitivity to the multisite fungicide captan. The lower label rate of captan applied preventively did not control isolates with reduced sensitivity on detached blueberry fruit. These findings suggest a potential population flow between strawberry and blueberry fields that may impact blossom blight and gray mold development in blueberry fields. The relatively lower fungicide input applied to blueberry fields compared with strawberry fields seems to be sufficient to select for resistance and multiple-resistant phenotypes in B. cinerea populations in blueberry.

First Report on Resistance to Pyraclostrobin, Thiophanate-methyl, Fenhexamid and Boscalid in Botrytis cinerea from Eucalyptus Seedlings in Florida Greenhouses.

Botryotinia fuckeliana de Bary (anamorph Botrytis cinerea Pers.) is an ubiquitous plant pathogen causing gray mold disease on more than 200 crops grown in the field or in greenhouses. Eucalyptus seedlings originating from three different greenhouses showing stem lesions were submitted to the Gulf Coast Research and Education Center Disease Clinic in June 2012. Ten single spore isolates of B. cinerea were obtained and tested for sensitivity using spore germination and germ tube elongation assays described previously (4). Fungicides tested were pyraclostrobin at 100 µg/ml (Cabrio, BASF, Research Triangle Park, NC), thiophanate-methyl at 100 µg/ml (Topsin-M, UPI, King of Prussia, PA), fenhexamid at 1 and 50 µg/ml (Elevate, Arysta Life Sciences, Cary, NC), fludioxonil at 0.1 and 10 µg/ml (Medallion, Syngenta Crop Protection, Research Triangle Park, NC), and iprodione at 5 and 50 µg/ml (Rovral, Bayer CropScience, Greensboro, NC) on 1% malt extract agar (MEA, 10 g malt extract and 15 g agar), and to cyprodinil at 1 and 25 µg/ml (Vanguard, Syngenta Crop Protection) on 0.5% sucrose agar (4). Sensitivity to the succinate dehydrogenase inhibitors (SDHIs) boscalid at 5 µg/ml (Endura, BASF), penthiopyrad at 1 and 3 µg/ml (Fontelis, DuPont Crop Protection, Willington, DE), and fluopyram at 3 µg/ml (Luna Privilege, Bayer CropScience) was evaluated on yeast bacto acetate agar (YBA) (3). The discriminatory dose for boscalid was adapted from (2) whereas those used for penthiopyrad and fluopyram were developed in this study. Isolates were grown on malt yeast extract agar for 7 to 10 days and spore suspensions were prepared in sterile distilled water and diluted to 106 conidia/ml. Respective media in 9-cm petri dishes were seeded with 7-µl droplets from each isolate allowing testing for all isolates on one plate. Two plates were used for each fungicide and sensitivity tests were repeated twice. Germination and germ tube growth were assessed microscopically after 16 to 24 h incubation at 22°C. The frequency of isolates resistant to two, three, and four fungicides was 90, 60, and 10%, respectively. Nine isolates (90%) were resistant to thiophanate-methyl and pyraclostrobin, simultaneously, whereas six (60%) and two isolates (20%) were resistant to boscalid and fenhexamid, respectively. All boscalid-resistant isolates were also resistant to pyraclostrobin and thiophanate-methyl, but one fenhexamid-resistant isolate was sensitive to the other three fungicides. Eight isolates that germinated at 5 µg/ml iprodione but not at 50 µg/ml were considered sensitive. All isolates were sensitive to the SDHIs penthiopyrad and fluopyram as well as to cyprodinil and fludioxonil. To our knowledge, this is the first report of resistance to pyraclostrobin, thiophanate-methyl, fenhexamid, and boscalid in B. cinerea from eucalyptus seedlings in Florida. The absence of resistance to fludioxonil and iprodione is likely because these fungicides are not registered in nurseries as well as fluopyram and penthiopyrad which were developed only recently. Management practices should be developed to limit the selection and spread of additional resistant populations in eucalyptus nurseries as has occurred in Florida strawberries where multi-fungicide resistance is widespread (1). References: (1) A. Amiri et al. Plant Dis. 97:393, 2013. (2) M. Leroch et al. Appl. Environ. Microbiol. 79:159, 2013. (3) G. Stammler and J. Speakman. J. Phytopathol. 154:508, 2006. (4) R. W. S. Weber and M. Hahn. J. Plant Dis. Prot. 118:17, 2011.

[Experimental investigation of canine echinococcosis from swine hydatic cyst in Mexico]. / Investigación experimental de la equinococosis canina a partir de quiste hidatídico de origen porcino en México.

OBJECTIVE: To evaluate the infection and obtain the adult state of the cestode, echinococcosis was reproduced in dogs using the hydatic cyst of swine. METHODS: Two groups were formed, one of five and the other of three dogs, each animal in the experimental group was given two grams of germinative membrane of fertile hydatic cyst by oral route. The second was the control group. Both groups were evaluated clinically, serologically and parasitologically. One animal was killed on the 35th day after infection and each five successive days until the 55th day. In the second group all the animals were killed on the 55th day. Eggs of the cestode were observed in feces from the 51st post-infection day. The morphological evaluation was made through microscopic observation of the mucous intestine scraping. RESULTS: Fifty cestodes were analyzed, ten from each of the infected dogs, 49 (98%) presented three proglottids and 1 (2%) had four; 18 (36%) of the cestodes presented a gravid proglottid. The length of the strobila varied from 1.6 to 2.6 mm. The average of the long and short hooks was 31 and 34, respectively. The length of the long hooks varied from 0.081 to 0.09 mm, the short hooks from 0.034 to 0. 041 mm. The quantity of plasmatic proteins and the number of leukocytes were significantly greater in the control group (P < 0. 05); the quantity of alpha-globulins was larger in the infected group (P < 0.05). CONCLUSIONS: The results confirmed the dog-pig cycle, a subclinical infection in the definitive hosts, that makes the diagnosis and control in species closely related to the human being difficult.