Twenty cranberry (Vaccinium macrocarpon) genotypes were evaluated for five seasons in an experimental upland planting in southwest Michigan. Beds were constructed on a silty clay loam soil by excavating to grade, and filled with 30 to 45 cm of sand. Four 2 × 2-m plots of each genotype were planted in 1996. Fruit were harvested with hand scoops from 2000 to 2005. Yield per plot, average berry weight, and percent berries exhibiting decay were determined. Sound fruit were also stored at 2 °C for 4 to 8 weeks and sorted to determine the percentage of fruit developing decay in storage. Fungi were isolated and identified by morphological characteristics. Genotypes producing the highest average yields were `Stevens', `Ben Lear', #35, `LeMunyon', and `Franklin'. Varieties with the highest average berry weight were `Pilgrim', `Stevens', `Baines', `Beckwith', `Searles', and #35. Genotypes with lower rot incidence at harvest were #35, `Early Black', and `Foxboro Howes', whereas `Howes' and #35 developed the least rot during storage. Fungi commonly isolated from decaying fruit were Colletotrichum sp., Coleophoma empetri, Phomopsis vaccinii, Phyllosticta vaccinii, Fusicoccum putrefaciens, Botrytis cinerea, Pestalotia sp., and Allantophomopsis sp. Prevalence of specific fungi differed among cranberry genotypes.
Seven primocane-fruiting and 15 floricane-fruiting raspberry varieties (Rubus idaeus) were compared for three fruiting seasons on a loamy sand soil in southwest Michigan. The earliest primocane-fruiting varieties (`Autumn Bliss', `Autumn Britten', `Polana') began ripening 3 weeks before the standard variety, `Heritage'. `Autumn Bliss' was the most productive early primocane-fruiting variety. `Caroline' and `Dinkum' ripened about 1 week earlier than `Heritage', and `Ruby' was 2 days later. `Caroline' was the most productive of this group and also had large fruit that were somewhat resistant to rot caused by Botrytis cinerea. `Caroline' also received the greatest leaf feeding from rosechafer beetles (Macrodactylus subspinosus). Most primocane-fruiting varieties were fairly resistant to leaf spot (Sphaerulina rubi), while `Dinkum' was highly susceptible to spur blight (Didymella applanata). Floricane-fruiting varieties were evaluated based on fruit production and quality as well as winter injury to canes, disease resistance, and feeding injury from two-spotted spider mites (Tetranychus urticae). The floricane-fruiting varieties showing minimal winter injury were `Boyne', `Killarney', `Latham', `Nova', and `Prelude'. `Canby', `Encore', `Glen Ample,', `Qualicum', `Reveille', `Titan', and `K 81-6' were moderately hardy; while `Tulameen', `Malahat', and `Lauren' were not hardy enough for this location. `Reveille', `Killarney', `Boyne', and `Prelude' were the most productive floricane-fruiting varieties. `Nova' and `Qualicum' had low levels of botrytis rot. `Nova' was most resistant to leaf spot and also had resistance to spur blight. Injury from mites was greatest on `Glen Ample' and lowest on `Malahat', `Prelude', `Qualicum', and `Tulameen'. `Caroline' (primocane-fruiting), `Prelude', and `Nova' (floricane-fruiting) were promising newer varieties.
The performance of four California and 11 eastern cultivars of Fragaria×ananassa Duchesne in Lamarck, and 12 elite F1 hybrids of Fragaria×ananassa with F. virginiana Miller in their immediate background was evaluated in a producer's field with and without methyl bromide-chloropicrin fumigation. Averaged across all genotypes, plants in nonfumigated soils had 43% fewer runners, 18% smaller fruit, and 46% lower yields than did plants on fumigated soil. They also had an average of 27% fewer crowns, 49% more root discoloration, significantly fewer fine roots, and showed symptoms of the black root rot syndrome. The most commonly isolated pathogens from discolored roots were Pythium sp., Rhizoctonia sp., Idriella lunata P.E. Nelson & K. Wilh., and the root-knot nematode (Meloidogyne hapla Chitwood). The performance of all genotypes was enhanced by fumigation, although the F. virginiana hybrids performed comparatively better than the other cultivars on nonfumigated soils.
Highbush blueberries (Vaccinium corymbosum L.) in Michigan are treated annually with fungicides to control fruit rots caused by Colletotrichum acutatum J.H. Simmonds,Alternaria sp., and Botrytis cinerea Pers.:Fr. Control with recommended fungicide programs is often inadequate. The goal of this study was to compare the effects of two spray treatments and three levels of pruning severity on fruit rot levels in mature `Jersey' bushes. Two spray treatments were tested for 3 years: 1) recommended fungicide rates applied with a conventional airblast sprayer; 2) 67% of recommended fungicide rates applied with a multifan/nozzle, above-row sprayer. Pruning treatments included light and heavy pruning (compared for 1 year), and light, moderate, and heavy pruning (compared for 3 years). Fruit rot incidence was determined after incubating individual fruit at 100% relative humidity and 21 °C for 7 to 11 days, and after exposing 0.24-L plastic clamshell containers of fruit to simulated commercial handling. The above-row sprayer provided fruit rot control at least equivalent to the airblast sprayer even though less chemical was applied. Anthracnose rot in berries from the top of the bush canopy were reduced by pruning, but those in the bottom of the bush, and levels of other diseases were not consistently affected. Pruning also reduced yields, although the study was too short in duration to determine the long-term impact on production.
Identical trials were conducted in a multibay high tunnel and an adjacent open field in southwestern Michigan to compare primocane-fruiting cultivars (Autumn Britten, Caroline, Chinook, Heritage) and floricane-fruiting cultivars (Canby, Encore, Heritage, Nova) of red raspberry (Rubus idaeus). Floricane-fruiting plots of ‘Heritage’ were pruned to produce fruit on floricanes and primocanes (double cropping). The most productive cultivars in both environments were ‘Nova’ and ‘Canby’ (floricane) and ‘Caroline’ and ‘Heritage’ (primocane). These cultivars produced annual yields of 5.5 kg·m−1 row in the tunnel and 2.5 kg·m−1 row in the field. The order of primocane harvest (earliest to latest) was the same in the tunnel and field: ‘Autumn Britten’, ‘Caroline’, ‘Chinook’, and ‘Heritage’. Cultivars with the greatest average berry weight in the tunnel and field were Encore and Nova (floricane) and Autumn Britten and Caroline (primocane). ‘Chinook’ and ‘Autumn Britten’ tended to have the highest incidence of gray mold (Botrytis cinerea) of primocane-fruiting cultivars, but incidence was similar in floricane cultivars. Overall mold incidence was 1% in the tunnel and 13% in the field. Leaf spot (Sphaerulina rubi), cane anthracnose (Elsinoe veneta), spur blight (Didymella applanata), and botrytis cane blight (B. cinerea) were common in the field but absent in tunnel. Phytonutritional analyses of primocane fruit indicated that genotype differences were not consistent across the two environments. Relative cultivar characteristics (harvest season, yield, berry quality) were similar in the field and tunnels, but the tunnel environment tended to increase plant vigor, yield, and fruit quality and suppress several diseases.