Sunday, June 19, 2016

Disease of Eggplant

The eggplants can be small to medium size when brown spots appear. Then the spots grow larger and the fruit falls to the ground. You might ask, "What is the problem?"

Quite simply, the fruit is rotting due to a fungus disease called phomopsis blight. It is fairly common in a wet environment and is caused by the fungus Phomopsis vexans. Splashing rain spreads this disease. Hot, wet weather increases the problem.

In addition to the fruit, leaves and stems can also be attacked along with a dying of seedlings. Severely infected leaves turn yellow and wither. Stems and branches may develop dry, brown, cracked and sunken cankers.

Fruit injury begins as a pale, sunken, oval area on the surface. The area will enlarge and become depressed. With one lesion or several spots coalescing, large portions of the fruit will eventually decay.

Control Measures
·      In areas of high rainfall, planting resistant varieties, if available, is the best control measure.
·      The phomopsis fungus will survive between crops in plant debris in the soil. Remove and destroy crop residues. It is recommended to wait three years before replanting eggplant, or related crops, in the same area.
·       Spacing the plants farther apart to allow for better air movement and quicker drying of the plant may help reduce severity of the disease.
·      Weed control is also advisable since the pathogen can survive on solanaceous weeds such as nightshades. 
·      Lastly, applying a copper based fungicide may help reduce spread of the disease.

Friday, June 10, 2016

When Are Pineapples Ripe?

The following information is applicable to pineapple varieties presently available in the marketplace, yellow or white.

Select a pineapple that is plump and fresh-looking. The leaves in the crown should be crisp and green with the body of the pineapple firm. A larger fruit won’t necessarily be better tasting or riper than a smaller one.

According to Maui Land and Pineapple Company, pineapples, unlike bananas, do not ripen after harvest. They may advance in shell color, but they do not get any sweeter; they actually begin to degrade. A pineapple on a shelf in the market is as ripe as it’s going to be.  In terms of sweetness, color is not an indication.  Often times, depending upon the weather, green fruit will be sweeter than yellow fruit.  The only true indication is the size and flatness of the 'eyes' of the fruit. Typically, the bigger the eyes and the flatter the eyes, the sweeter the pineapple will be.

The color of the outer shell of the pineapple is not necessarily a sign of maturity or ripeness: a pineapple’s flesh can be ripe, sweet, and ready to eat when the shell is still quite green. A University of Florida publication states, “For optimum fruit sweetness, pineapple fruit should be harvested when 1/3 to 2/3 or more of the peel color has turned from green to yellow.”  

Other indicators are as follows: a good, ripe fruit has a dull, solid sound; immaturity and poor quality are indicated by a hollow thud. If the pineapple is at its peak freshness, it will have a sweet and fragrant odor. If the odor coming from the pineapple smells too sweet and almost alcoholic, it is past its peak. If you don't plan to use your fresh pineapple right away, store it in the refrigerator, where it will keep longer. Generally, once it is ripe, fruit may be held in the refrigerator for up to a week. In addition, the ease of pulling leaves from the crown is not a sign of ripeness.

 Many years ago scientists classified fruits into two categories: climacteric and non-climacteric.  Climacteric fruit usually undergo dramatic changes during ripening. These changes have often been associated with a surge in respiration and ethylene production. Ethylene is a natural plant hormone.
The avocado, apple, melon and banana are classified as climacteric fruits whereas the pineapple is classified as a non-climacteric fruit.

 Non-climacteric fruit (oranges, pineapple, grape, watermelon) do not exhibit the increase in respiration or the rise in ethylene production. In addition, they normally do not undergo dramatic changes such as softening after harvest.

Tuesday, May 31, 2016

Bean Plants with Blight

Shown in the photo is a disease called halo blight, caused by the bacteria, Pseudomonas syringae pv. phaseolicola. It is spread from leaf to leaf and plant to plant in windblown rain or irrigation water. The bacteria enter the plant through wounds and natural openings when the foliage is wet and during periods of high humidity. The disease affects the seed pods as well as the foliage.

The first symptoms are small lesions resembling tiny pinholes on the underside of leaves. They rapidly dry and turn reddish brown and become visible on both sides of  the leaf. These spots usually remain small, but a characteristic yellow zone, resembling a halo, often develops around the lesions. They can be of irregular size and shape. Symptoms on the bean pods begin as tiny spots gradually enlarging to form dark sunken lesions. Infected pods are discolored and shriveled.

Control: There is some resistance to this blight. For instance, navy and small white bean cultivars along with some red kidney bean cultivars are resistant to halo blight. Check for resistant varieties in the type of bean you desire. Since the disease is spread by rain, it would help to provide some type of cover that would lessen water droplets falling on the plants. Although these products will not eradicate the disease, copper based bactericides can reduce infection and protect healthy tissue. Do not plant beans in the same location for 3 years.