Horticulture

Fruit

Uneven ripening is apparent in blackberries. Did the wet weather cause this?

Certainly the cool temperatures and lack of sunshine are prolonging the harvest season. Also, there was likely some winter damage on some of the less cold-tolerant blackberries grown in the state. Blackberries have primary buds and many have smaller secondary, or even tertiary buds. The primary buds set first fruit (that is the earliest to ripen) and the largest fruit. If low winter temperatures or spring frost injury occurs, the primary buds can be killed and then the secondary buds begin to grow and set a later, smaller crop.

— Answer by Michele Warmund

Ornamental plants

How do you control leaf spot on ornamental plants?

Fungi cause most leaf spot diseases on ornamental plants. Following an Integrated Pest Management approach, the first step is to try to keep the leaves as dry as possible. This year that has been nearly impossible. In more normal years, it means watering at the surface (e.g. drip irrigation) or, if overhead watering is necessary, watering early in the day so that the leaves dry quickly.

Ultimately, the application of fungicides is necessary to keep leaf spot to a minimum. Newer generation fungicides have systemic action and can’t be washed off the surface of the leaves like older, heavy-metal based fungicides could. Chlorothalonil and thiophanate-methyl are examples of fungicides that control a fairly broad range of foliar diseases.

— Answer by David Trinklein

Vegetables

Does this wet weather contribute to increased blossom-end rot in tomatoes?

Blossom-end rot is a physiological disorder caused by a lack of calcium. Calcium is taken up and moved through the tomato plant via mass flow, which is heavily dependent on water. When it rains a lot, the soil becomes saturated to the point of limiting the amount of oxygen to the tomato plant’s roots. This, in turn, adversely affects the integrity of the root surface, and makes it more difficult to take up water. Like tobacco, tomato displays water wilt quite readily when plants stand in water for any length of time.

— Answer by David Trinklein

How should you control and manage early blight in tomatoes?

We recommend an Integrated Pest Management approach to early blight control that begins with crop rotation. Tomatoes should never be planted in the same spot in a garden until three years have passed. Also, rigorous garden cleanup at the end of the year can help to reduce the incidence of residual inoculum. Next, keep the foliage as dry as possible by applying water via drip irrigation. Applying mulch to the soil can help prevent water from splashing soil that contains the inoculum of the disease on the lower leaves of the plant. Finally, chlorothalonil can be very effective as a preventative spray. Some growers rotate or tank mix it with a fix-copper product such as Kocide.

— Answer by David Trinklein

How should you control or manage water wilt of vegetable plants?

Trying to drain the area of standing water if at all possible is about the only thing that can be done if water wilt exists. Prevention for future years  is a more realistic way to manage it. Areas prone to cause water wilt should be amended with organic matter to help build soil structure and improve drainage. Planting on berms can also help. For very poorly drained soil, consider raised-bed gardening.

— Answer by David Trinklein