by Matt Lollar | Feb 24, 2022
We often think of plant pests to be only insects. However, plant pests can also be fungal and bacterial diseases, weeds, and even rodents. That’s right, rodents, like squirrels, mice, and rats! One particularly annoying rodent pest of the garden is the roof rat (Rattus rattus, a.k.a. citrus rat, fruit rat, black rat, or gray rat). Roof rats are native to southern Asia. This is the same species that was responsible for carrying the bubonic plague around the world. Roof rats are the most detrimental rodent pest to fruit crops in the state of Florida. In addition to fruit crops, they feed on stored animal and human food. Roof rats live in attics, soffits, walls, and outbuildings. They also chew through wires, pipes, and walls. Roof rats damage some fruit crops (like citrus and melons) by first creating a half dollar sized hole, then they hollow out the fruit. In crops without a rind or peel, like peaches and tomatoes, they just eat large chunks.
Roof rat damage to tangerines. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
Adult roof rats are 12-14 inches long with tails longer than their body length. In Florida they have been identified in three color phases: black back with gray belly; gray back with light gray belly; and brownish gray back with a white or cream colored belly. Other than fruit damage, evidence of infestation includes 1/4-1/2 inch long droppings and rub marks left along travel trails. Roof rats will travel up to 150 yards from their den for food and water. They breed year-round and have litters of 5-8 pups with a gestation period of only 21 to 23 days.
An adult roof rat. Photo Credit: Alabama Cooperative Extension System
A well-thought-out integrated pest management strategy is needed to control and potentially prevent roof rats on your property. Integrated pest management is a strategy consisting of multiple tactics to control a pest. These tactics include scouting (looking for evidence of the pest population); prevention; trapping and exclusion; biological control such as predators; and rodenticides and repellants.
- Prevention – Roof rats are good climbers and swimmers. It is important that fruit trees are planted away from the house, fences, and outbuildings. Make sure to prune fruit trees away from these structures if they can’t be removed or transplanted to another location. Also prune branches from touching the ground to help prevent rats from using trees for cover. Sheet metal (18-24 inches wide) can be loosely wrapped around the tree trunk to keep rats out of the tree.
- Trapping – Rat traps can be placed in several strategic locations. Traps (triggers facing down) can be attached to the trunks of trees. Traps can also be attached to the stringer boards on a fence. Make sure that traps are only set from dusk to dawn to avoid killing non-target species like birds and squirrels. Leave traps in place for at least a week before moving them because roof rats are cautious of new objects.
- Rodenticides & Repellants – Poisons should only be used after all other control methods are exhausted. Most products are very toxic to humans, pets, and wildlife. If used outdoors, poison baits must be placed in tamper-resistant bait stations.
- Biological Control – Rat snakes and king snakes are good natural predators for roof rats. If you have more open spaces you may consider building a barn owl house. Barn owls and hawks are also natural predators. You may also consider getting a farm cat to help control the population. Cats will kill juvenile rats, but have trouble catching adult rats.
Hopefully you will never have to encounter roof rats or other rodents invading your yard and house. However, if they do come around more information is available in the publication “Pests in and Around the Southern Home“.
by Ashley Stonecipher | Jan 26, 2022
Violas. Photo Credit: University of Florida/IFAS Extension
It is freezing cold this week and hard to believe that we are already talking about “What to Plant” and “What to Do” to get started early. In North Florida there are cool-season annuals that can be planted now. The list includes pansies, violas, petunias, and snapdragons. As we are coming to the end of January it is time to plant crinum, agapanthus and gloriosa lily bulbs. Make sure to mulch these areas after planting to protect them from the cold temperatures. This is also the month to plant camellias, which these come in many colors and forms that your local nurseries will carry this time of year. If you haven’t planted all your cool season crops there is still time to do that now such as broccoli, kale, carrots, and lettuce. Irish potatoes can be planted now as well.
Now you might be asking “What can I do?”. January is a great time to prune non-spring flowering shrubs and trees to improve their form. This is a good time to plant deciduous fruit trees, this will give their roots time to develop before the warmer spring temperatures. Since existing trees are dormant, it is a good time to prune and fertilize them. When the temperatures are near freezing many of the tender plants will need to be covered to minimize damage. It’s a good time to plant a tree. Hurricane-resistant trees include live oaks, bald cypress, cabbage palms, and southern magnolias. It’s time to remove those dead spent seed pods on your crape myrtles and removing any crossing branches and twiggy growth will improve the appearance and the form of the plant.
Potatoes planted in mid-February were ready to harvest in mid-May in Bay County. Photo: Vicki Evans, UF/IFAS Master Gardener of the plant.
As we go into February it will soon be time to apply a preemergence weed killer to your lawns to prevent warm-season weeds. Temperatures must rise to 65°F for 4 to 5 consecutive days before you do a preemergence application and make sure you are not using a weed and feed fertilizer. Citrus and other fruit trees can be fertilized at this time. The amount and frequency will depend on the age and type of fruit tree you are growing. Avoid pruning Citrus until spring to avoid any injury since cold temperatures are still possible. It is time to prune those roses this month to remove damaged canes and improve the overall form. After the pruning is complete you can fertilize and apply a fresh layer of mulch. They should begin blooming within 8 to 9 weeks after being pruned.
Dianthus, pansies, violas, and dusty millers are annuals that can take a chill and should be planted in February. You can continue to plant crinum and agapanthus this month and add on amaryllis and rain lily bulbs as well. If it has been dry make sure to provide plenty of water for the bulbs to establish and continue to protect them from the cold by adding mulch. Trees and shrubs will begin to bloom this month including red maples and star magnolias. Continue planting potatoes throughout the month and towards the end of February warm-season crops like tomatoes and pepper can be planted but be prepared to protect them from any late frosts.
by Mark Tancig | Jan 13, 2022
Asian citrus psyllid, Diaphorina citri. UF/IFAS/Entomology Photo: Michael Rogers.
In late 2016, as many of us were enjoying the harvests from our backyard citrus, a bacterial plant disease that can affect all citrus, citrus greening, was widespread in central and south Florida but had not made it this far north. That year, the vector, the insect that spreads the disease from tree to tree, had been found in Leon County and a few other surrounding Panhandle counties, but the disease had not. By mid-2017, the disease had been confirmed in Franklin County and we hoped that our cooler temperatures could keep the insect and disease at bay. Well, I regret to inform you that the disease has also now been confirmed in Leon County, growing in a residential yard in Tallahassee. Now that it is confirmed in non-coastal (and cooler) north Florida locations, I thought a review of the signs and symptoms – as well as what to do with your tree if you suspect or confirm greening – would be helpful.
The tricky part about diagnosing citrus greening is that it has symptoms that look very similar to soil nutrient deficiency symptoms, especially when first infected. This is a good time to mention that citrus require certain micro-nutrients for optimal growth and a citrus-specific fertilizer product should be used when applying fertilizer. Both the disease and certain nutrient deficiencies cause yellowing of the leaves. With greening, the yellowing is typically blotchy and/or not in any particular pattern. Nutrient deficiencies typically cause unique patterns of yellowing, such as a V-shape or artistic-like symmetrical patterns on each side of the leaf’s midvein. The soil’s acidity, or pH, can also cause some nutrients to not be taken up by the plant even if they are present. Soil testing, available from your local UF/IFAS Extension office, and scheduled fertilizations with a citrus-specific fertilizer can ensure that nutrients are not to blame for the discoloring of leaves. More advanced stages of the disease cause such symptoms as leaf drop, fruit drop, lop-sided fruit, uneven inner fruit cores, and reduced fruit quality.
Citrus greening symptoms of the fruit. Photo by Brooke Moffis.
A more obvious sign of potential problems for your citrus are the presence of the insect vector, the Asian citrus psyllid. This is a tiny little insect that goes from one leaf to the other sucking up plant saps for food and unknowingly spreading the bacterium responsible for citrus greening. You can monitor for them by looking closely at the new flushes of growth. If the psyllids are present, you will likely notice most their small, peach-colored eggs and/or white, waxy secretions. If found, it doesn’t necessarily mean that your tree has greening, but you will want to minimize the chance that they could carry it to your tree. The psyllids can be treated with pesticides, ranging from the less harsh options (horticulture oils, neem oil, kaolin clay) to the more hardcore stuff (malathion, carbaryl, imidacloprid). Of course, always read the label of any pesticide before use and/or consult a qualified landscape professional for assistance.
Blotchy leaf symptom of citrus greening. Photo by Jamie D. Burrow.
If you suspect your tree is infected, a diagnostic test can be performed by UF/IFAS plant pathologists at the North Florida Research and Education Center (NFREC) in Quincy to confirm. The test does cost $50, which may seem a little steep, but it’s an expensive lab analysis to run and may be worth piece of mind.
If citrus greening is confirmed in your tree, the right thing to do, unfortunately, is to remove and burn the plant material as there is no known cure. While the Florida Department of Agriculture and Consumer Services (FDACS) doesn’t have any removal requirements for infected dooryard citrus, tree removal is best to prevent additional spread of the disease to other trees, especially those grown by commercial producers in our area. This may seem drastic but eventually the health of the tree and quality of the fruit will decline to a point where you will want to remove it anyway. Don’t forget that movement of any citrus plant outside of the state is prohibited for the very reason of preventing spread of citrus diseases.
You may be asking, “Is it okay to replace it with another citrus tree?” The answer is yes you can, but you do risk re-infection and will want to be monitoring the new planting.
You may also be thinking, “What is going to happen to Florida citrus?” That’s a question that many researchers at UF/IFAS are trying to answer. There is some hope that intense irrigation and nutrient management, as well as specific pruning practices, can help infected trees continue to be profitable for commercial growers. Recently, UF/IFAS researchers were awarded several grants to try and figure a way out of this problem. Some of the lines of research focus on exploring the resistance found in different citrus varieties, including an Australian lime that appears to be greening resistant. This could potentially be used as a future rootstock. Another approach is to try and treat the plants with a particular peptide that would prevent the disease from binding in the insect’s gut. Isn’t that amazing?
Until a fix is found, we should be monitoring for this disease in our area and taking steps to reduce its presence through controlling the psyllids and removing infected trees. If you suspect a tree has greening, please contact your local county Extension office to review the symptoms and discuss your options.
Much more information on citrus greening is available at the following Ask IFAS website: https://edis.ifas.ufl.edu/entity/topic/citrus_greening and from this 2017 article – https://nwdistrict.ifas.ufl.edu/phag/2017/03/03/disease-alert-citrus-greening-and-asian-citrus-psyllids-found-in-the-panhandle/.
by Larry Williams | Jan 6, 2022
Q. When is citrus fruit ready to harvest?
Satsuma fruit ready to harvest. Photo credit: Larry Williams
A. Florida uses five indexes to determine maturity of citrus, including soluble solids, juice content, acid level, soluble solids/acid ratio and skin color. But, the home gardener can easily decide when most citrus types are ready to be harvested. As the fruit reaches full size and the skin color changes from green to greenish yellow to orange, simply pick some fruit and taste it to see if it is sweet. If not, wait a little longer (a week or two) and taste test another fruit. Meyer lemons are ready when the skin color changes from green to greenish yellow. Satsuma fruit may be ready to eat before the skin becomes completely orange, especially if the early fall is warm. Kumquats are usually at their peak in taste when they become fully orange.
Citrus fruit does not ripen additionally after it is harvested. So, let it mature sufficiently on the tree.
Harvest season for satsuma is October to December. Harvest season for Meyer lemon is November to March. Harvest season for kumquat is November to April. Most grapefruit have a harvest season from November to May. Harvest season for sweet oranges varies. Early season oranges are harvested October to January, mid-season oranges are harvested December to February and late-season cultivars are harvested March to June. Citrus fruit may mature a little earlier in the harvest season on mature trees and more toward the end of the harvest season on young, vigorous trees.
Q. What cold-hardy citrus is best for North Florida?
A. Citrus species are tropical and subtropical in origin. As a result, citrus is not well suited for extreme North Florida. Commercial citrus production has progressively moved further south in Florida due to historic freezes. So, you’d be wise to choose the more cold-hardy citrus types for our area. But, even cold-hardy citrus can be severely injured or killed by a hard freeze in North Florida.
Some of the better choices for cold-hardy citrus in North Florida include kumquat, satsuma, calamondin and Meyer lemon. There has been some success with grapefruit and sweet oranges in our area. Lemon and lime are much less likely to survive in North Florida. There has been some discussion concerning future success with growing citrus a little more north in its current range related to climate change. There already has been some success with growing the more cold-hardy citrus types such as satsuma and kumquat in middle Georgia. We’ll see how this works out.
More information on cold-hardy citrus is available from the UF/IFAS Extension Office in your County and through this link. https://crec.ifas.ufl.edu/extension/trade_journals/2018/2018_june_coldhardy.pdf
by Matt Lollar | Dec 16, 2021
Trees provide shade, aesthetics, and perspective to the landscape. However, they only serve as burdens if not properly selected and maintained. To help determine what trees do best under certain conditions and to provide information on tree care, this month’s Gardening in the Panhandle LIVE! was all about trees.
Florida maple beginning to exhibit fall color. Photo credit: Larry Williams, University of Florida/IFAS Extension – Okaloosa County
Tree Selection
Some trees grow faster than others. That’s not always a good thing, but if you’re trying to select a tree that grows fast and will provide shade in your yard then you might want to give the following species a try. Click on the links for more information.
A lot of times you’ll read a particular tree species prefers moist, well-drained soil. Some coastal soils are very well drained and require supplemental irrigation after establishment to keep some species alive. One tree that does well in sandy, well-drained soils without supplemental irrigation is the sand live oak. Another tree, that would never win a popularity contest, but does well in sandy soils is the sand pine. This tree has a gnarly growth habit, which would make it an interesting focal point in the landscape. Turkey oaks are another option for dry spots.
There are a lot of fruit tree species that can be grown successfully in the panhandle. The key to good fruit production is selecting trees that are adapted to the average number of chill hours (usually calculated by the number of hours between 34ºF and 45ºF) your yard receives on a yearly basis. Some peaches, plums, and nectarines have been developed for our climate. Citrus such as satsumas and tangerine hybrids grow well in the panhandle, but sometimes require cold protection. Persimmons, loquats, and pears are other fruit trees that grow well.
If you already have mature trees in your yard, then you may be looking for smaller, understory trees to enhance your landscape.
Living this far south, you often have to really seek out trees that change color in the fall. Dogwoods, Florida maples, and blackgum trees all have great fall color. Some of the red oaks also have nice fall color. Two that come to mind are the nuttall oak and the Shumard oak.
Trees can cause a lot of damage if planted too close to sidewalks or buildings. To determine if a tree will fit in a confined space, you will need to consider its mature trunk flare diameter.
Florida is the southern extreme for growing ginko trees. If you decide to plant a ginko tree, make sure to select a male cultivar to avoid stinky, slippery fruit.
To successfully plant a tree, you need to start with a healthy tree. If the tree you purchase was grown in a pot, make sure it isn’t rootbound and doesn’t have encircling roots. You also should inspect the tree’s form, branching structure, and look for the presence of included bark. Please read “Selecting Quality Trees from the Nursery” for more tips on what to look out for when purchasing a healthy tree.
Some trees are more tolerant than others of high winds and flooding. Please read this publication about tree failure from hurricanes to help determine what tree species are better adapted to these weather events.
Santa Rosa County Master Gardener Pruning a Stone Fruit tree at the WFREC. Photo Credit: University of Florida/IFAS Extension
Tree Maintenance
Armillaria is a common fungal pathogen that infects trees from their roots. Other major diseases are more specific to certain species. A more comprehensive list of tree and shrub diseases can be found on the Ask IFAS website.
Tree establishment period depends on a lot of factors. Once a tree is established, it’s roots can be equal to about three times the distance from the trunk to the dripline.
Part of the beauty of a bald cypress is its knees. However they can also be a nuisance for mowing and other yard maintenance. The purpose of cypress knees is a bit of a mystery and there are a lot of theories on the subject.
Fallen leaves can help add nutrients back to your yard. Even if you are trying for a manicured lawn, you may want to rake up the leaves and use them elsewhere in the landscape.
Regardless of the species, most fruit trees benefit from a good pruning. Deciduous fruit trees should be pruned to maintain good branch structure and form, while citrus may benefit from a light hedging.
Trees are a wonderful addition to any landscape, but it’s important you select the right tree for the right place. Hopefully this article provided some information to guide you in the right direction.
