by Carrie Stevenson | Mar 2, 2017
Small Fruit vs Normal
If we look at the big picture when it comes to invasive species, some of the smallest organisms on the planet should pop right into focus. A microscopic bacterium named Candidatus Liberibacter asiaticus, the cause of Citrus Greening (HLB), has devastated the citrus industry worldwide. This tiny creature lives and multiplies within the phloem tissue of susceptible plants. From the leaves to the roots, damage is caused by an interruption in the flow of food produced through photosynthesis. Infected trees show a significant reduction in root mass even before the canopy thins dramatically. The leaves eventually exhibit a blotchy, yellow mottle that usually looks different from the more symmetrical chlorotic pattern caused by soil nutrient deficiencies.
One of the primary vectors for the spread of HLB is an insect called the Asian citrus psyllid. These insects feed by sucking juices from the plant tissues and can then transfer bacteria from one tree to another. HLB has been spread through the use of infected bud wood during grafting operations also. One of the challenges with battling this invasive bacterium is that plants don’t generally show noticeable symptoms for perhaps 3 years or even longer. As you would guess, if the psyllids are present they will be spreading the disease during this time. Strategies to combat the impacts of this industry-crippling disease have involved spraying to reduce the psyllid population, actual tree removal and replacement with healthy trees, and cooperative efforts between growers in citrus producing areas. You can imagine that if you were trying to manage this issue and your neighbor grower was not, long-term effectiveness of your efforts would be much diminished. Production costs to fight citrus greening in Florida have increased by 107% over the past 10 years and 20% of the citrus producing land in the state has been abandoned for citrus.
Classic blotchy mottle in Leaves
Many scientists and citrus lovers had hopes at one time that the Florida Panhandle would be protected by our cooler climate, but HLB has now been confirmed in more than one location in backyard trees in Franklin County. The presence of an established population of psyllids has yet to be determined, as there is a possibility infected trees were brought in.
A team of plant pathologists, entomologists, and horticulturists at the University of Florida’s centers in Quincy and Lake Alfred and extension agents in the panhandle are now considering this new finding of HLB to help devise the most effective management strategies to combat this tiny invader in North Florida. With no silver-bullet-cure in sight, cooperative efforts by those affected are the best management practice for all concerned. Vigilance is also important. If you want to learn more about HLB and other invasive species contact your local UF/IFAS Extension office.
Asymmetrical Fruit
Typical nutrient deficiencies observed in leaf, on trees with heavy fruit load. Not related to Citrus Greening (HLB)
Article by: Erik Lovestrand, UF/IFAS Franklin County Extension Director/Florida Sea Grant Agent
by Les Harrison | Mar 2, 2017
Photo caption: Purple nut sedge is dormant, but quite alive and waiting for warm weather. The best hope for control is to use a pre-emergent herbicide in late February to early March which will prevent this exotic invasive plant from germinating.
Now that March is here the lawn becomes less of an abstraction and more reality.
The lawnmower is no longer silent, meaninglessly taking up space as the grass wakens from its seasonal stupor. Alas, the dormant state has ended as the days are already getting slightly longer.
There is still time to get started with preparations for the ideal spring lawn of 2017. Weather is getting warmer, there is plenty to do.
In addition to doing a soil test, mentioned in previous week’s articles, an accurate weed assessment is also necessary. Though not green and conquering new territory, some of the weeds remain with seed still attached and awaiting distribution.
If the seed are still on the plants, clip the seed pods or remove the plants with the seed intact. Dispose of these properly and do not give them a chance to spread and germinate.
Two notable culprits are nondescript lying dormant waiting for the return of warm, sunny weather. Purple nut sedge and chamberbitter still have countless nutlets and seeds connected to the parent plant.
Purple nut sedge, Cyperus rotundus, grows from every possible sunny location with soil. This non-native plant is a rapidly spreading perennial which will take every opportunity to colonize new locations.
The identifier purple is in its name because there is a purple-tinged section of this sedge where it emerges from the ground. The plant is sometimes referred to as purple nut grass because of its long narrow leaves and its erect growth pattern originating from a nutlike basal bulb.
Chamberbitter, Phyllantus urinaria, is an annual with produces great quantities of seed on the underside of its leaf stems. It will handle full sun or partial shade and quickly form cluster of plants, each contribution seed to the soil.
Areas in the lawn identified as having severe infestations should be marked now for treatment in the near future with a pre-emergent herbicide. This type of herbicide prevents the seed from germinating in the spring.
Purple nut sedge concentrations should be sprayed in late February to early March, and chamberbitter in April since these pest species germinate at different times.
Another winter task is to prepare for seeding bare spots in the lawn. Reading the seed tag attached to the bag should help make the product selection much easier.
Check to confirm the seed has been tested for germination within the year. Also, be sure the grass seed species will grow in Florida.
Sometime generic lawn seed mixes will contain fescue, bluegrass, orchard grass and others turf types which will not grow in north Florida. While they may germinate, their use will only ensure weeds get established for another year.
Lastly, sharpen the lawnmower blade. When the warm weather arrives the mower will be frequently used, but at least the neighbors will be envious of the great green lawn.
by Molly Jameson | Mar 1, 2017
Raised-bed gardening can maximize production in a small amount of space. Photo by Molly Jameson.
Want to start a vegetable garden, but don’t know where to start? Are you seeing rectangular boxes popping up all over your neighbors’ yards and wondering why? Well, I am here to spread the news of raised-bed gardening!
Raised-bed gardening is a convenient way to grow vegetables without worrying about the quality of your soil. This is because you will be bringing in a high quality soil mix to your site. Vegetable plants need nitrogen, phosphorus, potassium, and many other nutrients to grow and mature properly. In many Florida Panhandle soils, we either have too much sand, too much clay, and nearly always, not enough organic matter. Organic matter results from the various stages of decay of anything that was alive. Think of it as the “glue” that holds the soil together, improves both soil moisture-holding capacity and drainage, and slowly releases nutrients that become available to the plant.
Organic matter is the “glue” that will hold your soil together. Photo by John Edwards.
Although you could add nutrients and organic materials to your soil without building a raised bed, the walls of a raised bed will hold your soil in place, reduce erosion, and even help keep out weeds. Here are a few things to consider when planning the installation of a raised-bed garden:
Location
The most important thing to consider when picking your location is sunlight. Vegetable plants need a lot of direct sunlight for optimum production. Leafy vegetables (lettuce, kale, arugula) can tolerate four to five hours, but fruiting crops (tomatoes, squash, peppers) generally need six hours of full sunlight to grow strong and produce fruit.
When starting a garden, remember that we are in the northern hemisphere, and this means the sun dips to the south, especially in the winter. Objects therefore cast a shadow to the north, so pay attention to the position of southern tree lines, houses, and anything else that may block the sun. If you must choose, morning sun is better than afternoon sun, as afternoon sun can be very extreme in our area, especially in the summer.
Lastly, consider visibility! If you stick your garden in the very back corner of your yard, how often will you see it? The more visible it is in your daily life, the more likely you will notice easy-to-pull weeds, when your garden needs watering, what is ready to be harvested, and everything else that goes on in the garden.
Although wood is most popular, you can use materials such as concrete, bricks, or tiles to build a raised bed. Photo by Molly Jameson.
Materials
Now you have chosen a perfect garden location. What materials should you use to build your raised bed? Lumber is the most popular material. But you could use concrete blocks, bricks, tiles, or anything else that can support soil. You can make your beds as long as you like, but the important thing to remember is not to make the raised bed wider than four feet. This will allow you to reach all areas of your soil without stepping into the bed, which causes compaction. If you are working with kids, two or three feet wide is even better. You should make the height of your bed 10 to 12 inches, which will allow good drainage and enough space for your vegetable plants to develop strong roots.
When choosing lumber, you can go with untreated or treated wood. Within the last 15 years, wood preservatives considered unsuitable for raised-bed gardening have been phased out. There is well-documented research that has shown the newer products are considered safe for gardening. Although untreated wood typically will not last as long as treated, even treated wood will still begin to decompose after a few seasons. Either way, connect your wood with lag bolts, instead of nails, to hold the wood together tightly.
When filling a four ft. by eight ft. raised bed, you will need about 1 cubic yard of soil mix. Photo by Molly Jameson.
Soil
Now that you have your raised-bed structure built, what will you put in it? There are many landscape and nursery companies that can offer vegetable garden soil mixes for purchase in bulk. Typically, they will be about 50 percent compost (organic matter) and 50 percent top soil (nutrient-containing minerals). If you are filling a four foot by eight foot by 12 inch raised bed, you will need about one cubic yard of soil mix, which typically costs $30 to $60. This is about the volume of the back of a pick-up truck. If you do not have access to a truck, most companies will deliver in bulk for a $30 to $50 fee. This could be worth it if you are filling up multiple beds! Seasonally, you will then need to top off your raised bed as your soil will shrink as the organic materials decompose. But for this, you can buy bagged soil mixes or make your own compost.
The last step is filling your raised bed with vegetable plants! This could also be considered the first step… as you now must consider plant spacing, spring vs. fall vegetables, seeding into the garden vs. using transplants, trellising, pest control, harvesting…but we’ll save all that for future articles. Happy gardening!
