You probably have seen them and not given them much notice, growing among your blueberry fruits. They look like something just went wrong in fruit development. These are mummy berries and they are actually part of a fungal pathogen, Monilinia vaccine-corymobosi. This is a blueberry disease!
Mummy berries are caused by a pathogen
Over the season mummies fall off of the plant and oversummer and overwinter on the ground. When conditions are just right in the spring, these bodies will germinate and can produce 650,000 disease-causing ascospores. The ascospores can re-infect your plants creating a disease cycle.
Control is not difficult for hobby blueberry growers
This disease affects leaves and affects the fruits when the pathogen is spread to the flower bloom, by wind or by insects. For commercial growers this can be a serious problem. For the casual blueberry grower it is much easier. Simply remove the mummies and throw them away. Also, check the ground to remove those mummies that have fallen.
For those of you interested in pathology, Jade Florence has an excellent article, Mummy Berry, in The Plant Health Instructor. If you are unsure if mummy berry is your problem, contact your local UGA Extension office for assistance. If you don’t have blueberries in your community garden, they are a great addition and easy to plant.
Crop rotation is a huge part of integrated pest management (IPM) in Georgia vegetable production. It is an inexpensive tool in disease and nematode management. Correctly using crop rotation can cut down on pesticide use and result in healthier plants. Growing Vegetables Organically has some great information on this type of IPM.
As we are all planning our warm-season gardens crop rotation is something to consider. However, it is a whole lot easier to rotate crops around a 3 acre farm than it is to move them around a 32 square foot garden plot. How do we practice crop rotation in the community garden? It is even necessary?
Crop rotation has been around for centuries. Simply it is changing what is planted in a particular area each year. Planting the same crop year after year in the same location causes disease pathogens to build up and become a real problem. Rotating crops helps break this disease cycle. Also, since different crops use varying amounts of plant nutrients, crop rotation is a wise use of the nutrition in your soil.
Plants can be divided into families. Learn those plant groupings because many pathogens infect crops in the same families. The basic rule of crop rotation is:
Don’t plant crops from the same plant family in the same place every year.
Onion family (Alliaceae): chives, onions, garlic
Cole family (Brassicaceae): lettuce, collards, cabbage, broccoli, spinach
Squash family (Cucurbitaceae): pumpkins, watermelon, squash, cantaloupe
Bean family (Fabaceae): beans, peas
Tomato family (Solanaceae): tomatoes, peppers, eggplant
Since tomatoes and peppers are in the same family (Solanaceae), don’t plant tomatoes where you have been growing peppers. And, don’t follow squash with pumpkins (same Cucurbitaceae family). Many farmers follow a four year or even longer rotation plan. Their lettuce won’t see the same piece of soil for several years. This helps lower disease pressure and cuts down on fungicide use. Many Master Gardeners usually try for a three year rotation for a large garden area.
We know that crop rotation works to help create healthier plants but how does that translate in a Georgia community garden plot?
The best way is for the community gardener to choose plants from different families each year. This isn’t always practical. A gardener wants to grow what his/her family likes to eat. That may mean beans every year. The #1 vegetable grown in community gardens is tomatoes – year after year!
So, maybe you work with your fellow community gardeners and rotate who grows tomatoes and you all agree to share the tomato harvest. This may not always work, either. Some gardeners want lots of tomatoes every year.
Move your pole beans to the other side of the plot this year. Buy your tomatoes from the farmers market this year and try growing squash. Better yet, try growing and eating something entirely new.
At the very least Bob Westerfield, UGA vegetable specialist, recommends turning your soil over. Dig deeply bringing up soil that hasn’t been exposed to the sun. Go as deep as you are able. In a small way you are not rotating your plants but rotating your soil. Your UGA Extension agent can help you come up with a plan for crop rotation that will work for your situation.
You may have heard about integrated pest management (IPM) and wondered if it is something only farmers use. Actually IPM has a real place in any type of gardening, including your community garden plot. According to the UGA Integrated Pest Management website this is the definition of IPM:
It is a science-based decision making process that employs biological, mechanical, cultural, and chemical control methods in such a way as to minimize economic, environmental, and public health risks associated with pests and pest management practices.
Notice it is science-based decision making. This is important.
In practice, the gardener employs many different strategies to combat an insect pest or disease instead of just reaching for the chemical spray. For a very basic example a gardener wants to grow tomatoes knowing that Fusarium wilt can be a problem. (Fusarium wilt is a fungus that lives in the soil and infects plants through their root systems.) This gardener will employ IPM by:
making sure his/her soil is healthy
growing healthy plants using recommended fertilization and watering practices
learning about the Fusarium wilt fungus and its biology
choosing tomato cultivars that show resistance to Fusarium wilt – these will have the letter “F” after the cultivar name
caring for garden equipment by proper disinfection and not using equipment from another gardener that has not been disinfected
being aware of the hot, dry weather that favors Fusarium wilt and looking for wilting especially during these conditions
destroying any infected plants
practicing crop rotation
With IPM, actions are taken to prevent diseases and pests from becoming a problem. Rather than simply eliminating the pests that are found right now, using IPM means the gardener will look at environmental factors that affect the pest and its ability to do damage. Armed with this information, the gardener can create conditions that are unfavorable for the pest. Know your enemy!
Your local UGA Extension agent can help you make a positive disease or insect identification so that you can make a plan to deter the problem.
Learning when and where an insect pest lays her eggs can help you find those eggs and remove them. Determining what weather conditions favor a disease can help you adjust your planting date to avoid the peak of the disease. Finding out how a disease is spread can also help you combat it. Is it soil-borne or are fungal spores spread with wind? Also, what beneficial insects prey on your insect pest and how can you attract those helpful insects?
Subscribing to this blog and other researched based information sources can help you know what diseases or pests are problematic in your area and what you can do about them.
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