Visible quiescent infections were detected as small (<1 mm) necrotic flecks on green cv. Bing cherry fruit and as reddish halos surrounding tannish spots (1 to 2 mm) on immature, yellow-pink cv. Rainier cherry fruit in commercial orchards in California. Monilinia fructicola or Botrytis cinerea, the fungal pathogens causing brown rot and gray mold of cherry fruit, respectively, were isolated from most of the viable infections. M. fructicola was isolated more frequently from quiescent infections than B. cinerea in two years of the study, whereas similar isolation frequencies for both fungi were obtained in the other two years of sampling from one commercial Rainier cherry orchard. Using immature-pink Bing fruit that were inoculated in the laboratory, significantly more visible quiescent infections than active decay were reproduced in 6-, 9-, or 12-h wetness-period treatments after inoculation as compared to 18- or 24-h wetness periods where more active decay developed. Non-visible quiescent infections of M. fructicola or B. cinerea of immature Bing and Rainier fruit collected 2 weeks before harvest were identified on surface-sterilized, paraquat-treated fruit. In both years of the study, significantly more brown rot and gray mold occurred on the surface-sterilized, paraquat-treated fruit than on the non-treated or surface-sterilized fruit, indicating the presence of non-visible quiescent infections by these fungi in cherry fruit. Thus, for the first time, we demonstrated the presence of visible quiescent infections caused by M. fructicola and B. cinerea and we confirmed the occurrence of non-visible quiescent infections in sweet cherry fruit in California.
Quantitative Feedback Theory (QFT), a robust control design method introduced by Horowitz, has been shown to be useful in many cases of multi-input, multi-output (MIMO) parametrically uncertain systems. Prominent is the capability for direct design to closed-loop frequency response specifications. In this paper, the theory and development of optimization-based algorithms for design of minimum-gain controllers is presented, including an illustrative example. Since MIMO QFT design is reduced to a series of equivalent single-input, single-output (SISO) designs, the emphasis is on the SISO case.
New reduced-risk fungicides are highly effective in managing both pre-and postharvest diseases of stone fruit crops in California, and they have replaced most previously registered materials. These fungicides have a low impact on the environment, high specificity to target organisms, and low potential for groundwater contamination and human health risks. In stone fruit, they can be successfully used to manage brown rot blossom blight in a new delayed-bloom fungicide application program for lowprecipitation years. In our studies, we found that fungicide treatments applied 1 to 14 days before harvest were also effective against preharvest brown rot and protected fruit from fungal decays initiated during harvest. Practices such as mixtures and rotations can be implemented to prevent resistance from developing and to ensure the lasting efficacy of these reduced-risk fungicides.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.