Plant Diseases Management

Grape flowers and fruit set is a very complicated process, which can be influenced by cultivar, environment, vine status and history, biotic and abiotic factors. Optimum conditions for fruit set include high light intensity, warm temperature, and adequate soil moisture and nutrients at bloom. Good fruit set is important for proper cluster formation, development, and ultimate desired maturation and harvest of fruit. The following is some basics on fruit set and some potential causes of poor fruit set.

The Crop Protection Network (cropprotectionnetwork.com) is a national working group comprised of Extension agents and specialists from across North America that provide data through publications regarding pest management in agronomic crops. The website and publications can be a great resource for your operation. The following are the most recent fungicide efficacy tables for foliar diseases of corn and soybean.

The Brown marmorated stink bug (BMSB) Halyomorpha halys (Figs. 1 and 1a) was accidentally introduced into the United States in shipping containers arriving from Asia. The first confirmed specimen was collected in Allentown, PA in October 2001, although there is evidence that it was collected from black light traps in New Jersey as early as 2000.

Spotted-wing drosophila (SWD, Drosophila suzukii) is a small fly that lays its eggs into ripening and ripe soft-skinned fruit, causing direct damage and wounds that other pests and pathogens can use. Although they prefer fully colored ripe fruit, they are capable of infesting fruit that is just starting to turn color and will do so when populations are high.

Timely Viticulture is an electronic newsletter designed to remind grape producers of seasonal vineyard needs and considerations throughout the year.

The Spotted Lanternfly (SLF) is now confirmed in Cecil and Harford Counties in Maryland, and has the potential to be a very significant pest in vineyards. For background information, please see the TimelyVit Spotted Lanternfly (SLF) I—Background, for basic information. This Timely Viticulture was created to give growers information of how to scout for the pest and some management options and strategies.

Now is the time to remove the egg masses that the adult spotted lantern fly (SLF) laid last year. To do this you will need some hand sanitizer, a plastic bag, and a firm card for scraping.

Managing Downy Mildew of Cucurbits

Downy Mildew of Lima Bean

Difenoconazole is a sterol-inhibiting (SI) fungicide recently registered for use on grapes and other fruit. It belongs to FRAC Group 3, along with myclobutanil (Rally), tebuconazole (Elite, Tebuzol, Orius), and fenarimol (Vintage, formerly Rubigan). Difenoconazole protects vines and fruit from powdery mildew (PM), black rot (BR), and Phomopsis cane and leaf spot.