Southern highbush blueberry (SHB) is the primary blueberry species grown in Florida. It is dependent upon pollinating insects for adequate pollination and fruit set. Some Florida growers reported cases of low fruit set this past season, in particular on Meadowlark and Emerald, which may have been due in part to poor pollination. In most of these cases, growers observed a heavy bloom followed by poor fruit set, with undeveloped fruit dropping from the plants. Although there may be other causes for this scenario, including heavy flower thrips damage to blossoms, this description is generally indicative of poor pollination. Other symptoms of inadequate pollination include an extended period after flower opening before petal fall, petals turning brown while still on the bush, and a low number of seeds in fruit that does develop. This article will present current best practices to reduce the possibility of poor pollination of SHB.

We are EXCITED to announce the Florida Blueberry Growers Association Fall 2018 Meeting & Trade Show will be held on Tuesday October 30th at a NEW location, conveniently located off I-75 in Ocala, FL. This will be a day-long event of educational seminars as well as the opportunity to visit with 35+ vendors to the blueberry industry. Lunch is included in your paid registration.

Algal stem blotch is a disease caused by a plant-parasitic alga (Cephaleuros virescens) that can infect southern highbush blueberries and has been observed on various cultivars by Florida blueberry growers. The alga is thought to enter the plant through natural openings and wounds, which may include pruning cuts, and the disease appears to be more severe on stressed plants or plants greater than five years old.
Initial infections may take up to one year to produce symptoms. Reproductive spores are produced between May and September during wet conditions and are dispersed by wind and water. Overhead irrigation may contribute to conditions favorable for disease development and spread; where possible, drip irrigation should be used instead of overhead when this disease is present. Early symptoms include small red blotches or lesions on young stems that expand to form irregular patches and can encircle canes (Figure 1). When conditions become more humid, orange mats or tufts of algal growth appear from the lesions (Figure 2). In addition, canes with pale yellow to white leaves and stunted growth typically appear as the disease advances (Figure 3). The primary impact of this disease is a reduction in plant vigor, with a lack of regrowth in major canes following summer pruning in some cases. This damage can also leave the canes susceptible to Botryosphaeria, which can lead to cane dieback. Starting new plantings with disease free stock can help to avoid disease from the outset. When infection does occur, algal stem blotch can typically be managed (but not eradicated) through the use of copper hydroxide fungicides. These products should not be mixed with fertilizer, acidifying buffers, insecticides, or fungicides with EC formulations. Spray applications should be made beginning after harvest is completed, every four weeks at the label rate (or every two weeks at a lower label rate for severe infections) through September or October, making sure to have good canopy penetration and cane coverage. Applications on this schedule must be made consistently in order to be effective. Although this won’t have an impact on current symptoms, it will kill the reproductive structures to minimize the spread and infection of new plant tissue. Maintaining good management practices (irrigation, fertilization, disease, and pest control) can reduce plant stress, making them less susceptible to disease. In addition, removing and destroying infected canes and improving air circulation in the canopy through pruning may help minimize the spread of algal stem blotch.

To the membership of the Florida Blueberry Growers Association.

Recent enhancements to FAWN allow for easier navigation on station-specific pages, plus an app for smartphone access