Commercial Horticulture > Comm Hort Blog

Inspection Report Week of May 6, 2018 - Florida wax scale is right on schedule.  May 18 and August 23 have always stuck in my mind as the ideal times to spray, or at least look for, this pest.  The first generation can be easily controlled now.  The second generation will be in August.  Hosts include cornuta and crenata hollies, camellia, citrus, cleyera, crapemyrtles, deodar cedar, golden euonymus, Indian hawthorn, itea, and oaks.  I know of some live oak trees in Daphne that are covered with this pest and and resulting sooty mold.

Bagworms typically emerge around the first of May on junipers and Leyland cypress.  They will be small right now and blend in with the foliage as they use plant tissue to cover themselves.  Citrus leafminer has been reported around this time as well.  Normally treatment is not needed on older trees with lots of foliage, but treatment may be desirable every two weeks if there is not much foliage or the tree is small.  Trees recovering from freeze damage may need attention.  Garden fleahoppers were seen on lantana and pentas, causing white spotting on green leaves similar to lace bug damage on azaleas.  Chilli thrips were seen on distyllium.

Japanese beetles showed up in traps in Axis on May 7.  So far they've stayed in a small area about ¾ of a mile across since 2014.  They will be active from now until the end of June.  If anyone sees this beetle anywhere else in the county, please let me know.

Albert Van Hoogmoed

AL Dept of Agriculture, Mobile County

Spray equipment.JPGInsect pests can cause major crop loss or contamination if not managed timely. We are generally very careful about choosing the right insecticide, but we forget to check the condition of the spray equipment that leads to insect control failure even with the best of products. Poor spray application can also result in wasted products. Here are some quick reminders as the summer season starts.

  • Select the most appropriate sprayer based on insecticide label recommendations. Insecticides are available in a range of formulations, from liquids to dusts, emulsifiable concentrate to wettable granules. Some insecticides may not need any separate equipment as they are injected through the drip irrigation system for uniform application. Many new backpack sprayers have battery-operated pumps (Hudson Battery Power Sprayer, Solo 475-B Professional, Chapin 63985 4-Gallon Wide Mouth Sprayer, etc) that can provide good coverage with insecticides inside dense canopy.
  • When purchasing small capacity backpack sprayers, choose the ones with thick walls (indicating quality) and wide opening on top for easy fill. A pressure release valve helps to quickly reduce excess pressure for cleaning or other applications. A metal spray boom with good quality nozzle can reduce leakage that occurs with cheap sprayers. Leaking spray boom can cause undesirable pesticide exposure to the applicator. On small farms, it is good to have separate backpack sprayers for insecticide and herbicide applications.
  • Check the wear and tear on the nozzle every year. Certain products with low water solubility can be very abrasive to the nozzles causing them to change spray patterns. Insecticide applications are generally made using hollow cone nozzles to get small spray droplets. Having the correct nozzle and spray pressure reduces drift and chances of misapplication especially on diversified farms (i.e., diverse crops planted close together).
  • Be careful about multiple product mixes (insecticide + fungicide or multiple insecticides) as incompatible products can settle down into a sludge and damage spray equipment. Unless recommended by the insecticide label, do a jar test with new materials to test compatibility. Keep good records of application rates and spray mixes for future reference.
  • Insecticides generally require fine spraying with spray droplet size of 150 to 250 micrometers. Herbicide and fertilizer applications may require much coarser spray volume. In small plot organic research with various hand-held or backpack spray equipment, spray applications from bottom of plants with nozzle facing upward at an angle has performed better than top-down spray applications where the product simply rolls off the leaves. Add a spreader/sticker to increase product retention and distribution on plant leaves.
  • Calibrate sprayer to reduce the amount of product needed. Adjust the amount of product needed by reading the label and considering targeted application of insecticides. Pay attention to spray volume so that the product doesn't get too diluted. Don't drop insecticide rate of application below the minimum recommendation on the label – cutting rates may cause control failure and promote insecticide resistance development.
  • Wear appropriate personal protection equipment (PPE) whether you are going to apply conventional or organic insecticide. Taking proper precaution for protecting personal health is important. Contact the Pesticide Safety Education program in your state for training on PPE and Worker Protection Standards mandated by the EPA. When in doubt, contact your extension office and get updated training on important farm and food safety regulations.

For further reading:

New Home and Urban Garden IPM Slide Chart

A brand new Urban Farm IPM Toolkit is now available for urban farmers and community gardeners. This wheel slide chart has both conventional and organic insecticide listings for nearly 20 different crops. This publication also has listing of common insect pests with images that may help when scouting garden vegetables. Email to get your own copy. Don't forget to visit the Alabama Vegetable IPM website ( for IPM videos and other publications. 

Ayanava Majumdar, Extension Entomologist

May 10, 2018 - In recent a few weeks, most of the south Alabama was warm and dry, mostly dry. We have not had any rainfall for over two weeks in a row and this is taking a toll on row crops. Many people cannot plant their dryland fields and the crops planted are suffering drought stress. I have received several calls and texts regarding the concerns of soil herbicides sprayed behind the planter may not get activated. So, I am writing this timely information sheet to further discuss this issue.


1.       No chance of rain in forecast for the next 10-14 days. Should I still spray soil herbicides behind planter after I plant my dryland field?

I am a big advocate of using soil herbicides for weed control. However, in this case, I would suggest only spraying Gramoxone or Liberty behind the planter to smoke the weeds and start clean. We all know a fact for soil herbicides: it does not matter if it does not rain. They will not do you much good if there is no rain to activate them.


2.       If I did not spray soil herbicides behind the planter, what do I need to do next?
My first thought is I hope you sprayed a good residual herbicide treatment in your preplant burndown application, so you may still have some herbicide residues in soil. If you did not spray any soil herbicide behind the planter, I would do postemergence treatment very timely when you know you will have a high chance of rainfall. Weeds will not germinate or grow much in a very dry situation, so spraying a residual herbicide such as Warrant, Dual Magnum, or Outlook with Roundup, Liberty, Enlist Duo or One, or Roundup + Dicamba within 3 days before you get a rainfall is very important. In peanut, you can spray either Warrant, Dual Magnum, Outlook or Zidua with a postemergence herbicide such as Cadre, Blazer or Cobra. Weeds always make a flush after the rain if it has been dry for a while. Therefore, I suggest growers spray residual and foliar herbicide before the rain and hammer them hard with a follow up treatment 14-21 days later if escaped weeds start to grow fast after the rain.


3.       What do I need to do when I burn off emerged weeds behind planter and it is dry?
It is likely that these weeds are in a drought stress too, so they may not respond to herbicides super well. They also can grow thick leaf cuticle and wax layer so herbicide absorption will be lower than normal. I would suggest growers using crop oil concentrate or methylated seed oil instead of non-ionic surfactant (NIS) because oil-based surfactant may dissolve cuticle wax better and allow more herbicide to get into weed foliage. Adding liquid ammonium sulfate may increase control of certain weeds. If you happen to get a shower, although it may be a very small one, it can still help you burndown weeds better after a little bit of moisture, and I would take advantage of that before it gets very dry again.


4.       How much rain do I need to activate my soil herbicides?
Not a lot, 0.5 inch of rain can usually do it. For some soil herbicides, they can be activated with as little as 0.25 inch of rainfall. In a previous study, 0.5 inch of simulated rainfall was able to activate Brake, Reflex, Diuron, Cotoran and Warrant for pigweed control. However, with only 0.25 inch of rainfall, Brake + Reflex was the only treatment that provided over 90% pigweed control. Brake + Warrant provided 73% of control which is better than Brake (43%), Brake + Cotoran (32%) and Brake + Diuron (40%). See pictures below (pictures credit to SePro). 

Palmer amaranth control after 0.25-inch total irrigation at 7 days after application 

                              Brake 16 oz/A                                                  Brake 16 oz + Reflex 12 oz/A


  1. Which soil herbicide last longer on soil surface when there is no rain?

 I probably have been asked this question a hundred times so far, so I decided to run a large study to evaluate persistence of common cotton and peanut residual herbicides on soil surface before they can see a rainfall. More results will be available later in the fall.

Armillaria root rot (ARR) disease in grapes is caused by the fungus Armillaria mellea that infects grapevine roots, killing the cambium, and decaying the underlying xylem. ARR is native to many regions and can infect hundreds of woody plants. Host plants include broad-leaved trees in oak woodlands and stands of conifers. Agronomic hosts include stone fruits, nut trees, currants, gooseberries, nut trees, roses, strawberries, and other rosaceous plants such as raspberries. Peaches, nuts and almonds are much more susceptible to ARR than grapes.

Exposure of the crown area of vines with Armillaria root rot reveals white mycelial fans of Armillaria mellea.

Photo credit: Jack Kelly Clark.

Vines infected with Armillaria root rot become nonproductive and often die within 2 to 4 years after the first appearance of symptoms, which typically start as a slight stunting of shoots that progresses each year. Severe symptoms include shorter canes with dwarfed and chlorotic leaves. Adjacent vines often become infected as well. The pathogen forms a white mycelial mat under the bark at or below the soil line. These structures can often be observed in symptomatic vines by digging down about a foot below the soil line and removing thin layers of bark from the root collar.

The trunk below the mat is often visibly rotted, with a soft, spongy consistency and light brown color, as compared to white, dense wood on the portion of the trunk that has no sign of the pathogen. This fungus may form mushrooms at the base of infected vines that produce wind-blown spores, but these spores are not a significant means of infection to healthy vines. The fungus spreads vegetatively below ground. The fungus can survive on woody host roots long after the host dies.  When infected plants are removed, infected roots that remain below ground serve as a source of inoculum for vines planted in the same location. Healthy grapevine roots become infected when they come in contact with such inoculum. The fungus is favored by soil that is continually damp during the growing season.


What a grower can do?

The best management strategy is to remove residual roots before vineyard establishment. In diseased vineyards or sites supporting woody plants, use deep ripping to bring thick, woody roots and root crowns to the surface and then remove. This sanitation measure is much more efficient than fumigation alone. There are no known Armillaria-tolerant grape rootstocks. If possible, avoid planting sites infested with Armillaria. For chemical control follow the link to the Southern Region Small Fruit Consortium Bunch Grape Integrated Management Guide

 Elina Coneva 

Extension Fruit Crops Specialist

Pruning helps to maintain a balance between vegetative and reproductive growth. If you don't prune or prune very little, your tomato plants will produce excessive vegetative growth with reduced fruit size. Moderate pruning will leave your plants with shorter vines and larger fruit that will mature earlier.

Pruning combined with staking keeps vines and fruit off the ground, helping to control diseases. Although pruning requires some effort, the benefits of doing so are more marketable fruit, and easier harvesting.

The most common method of pruning is to prune to a two-stemmed plant by pinching off lateral branches (suckers) as they develop in the axils of each leaf. To achieve this balance, remove all the suckers up to the one immediately below the first flower cluster. A single pruning will usually be adequate, although a later pruning may be needed to remove suckers growing from the base of the plant.

Suckers should be removed when small, no more than 2 to 4 inches in length, because letting them get large wastes plant energy and provides an entry point for plant pathogens. Prune early in the morning after plants have dried.

​Inspection Report Week of April 16, 2018- 

April 6, 2018:  Aphids were seen on the tip of a camellia.  Ants were tending them, collecting honeydew produced by the aphids. Two small fly maggots were also present.  On April 9 the aphids were virtually gone.  Parasitic wasps had killed many, turning them into incubators (mummies) for developing young.  Fly larvae were growing big and fat on aphids. Biological control in action!

The pictures were taken with an iPhone set to a 3-second timer while holding a black piece of posterboard behind the plant. When ants are seen running around in a plant, it means that there is a honeydew producer at work. 

A few redheaded flea beetles were seen on weigela, hydrangea, and ‘Ebony Embers’ crapemyrtle.  Chilli thrips and lots of scarring were seen on ‘Conversation Piece’ azalea liners.  Redbanded thrips were seen causing serious damage on distyllium liners.  The host range for this pest seems to increase every year.  They started out on azaleas, then showed up on small pitcher plants, Drift roses, autumn ferns, wax myrtles, and now on distyllium.

Reminder for nurseries:  Several of the copper compounds have labeling requiring warnings after spraying. 

soaker irrigation in home garden.JPGWater management is one of the most critical issues in modern agriculture. Water resource has been critical to farmers since the advent of agriculture; poor management of this resource has led to many disasters around the world. Proper and timely irrigation is one of the first requirements of a sustainable integrated pest management or IPM system since it is linked to the overall plant health. Mismanaged water in a vegetable garden or farm can lead to sick plants that makes them more vulnerable to insect pests. In a vegetable farm or garden, water can be managed with some simple and smart ways. Here are a few tips for water management in vegetable production from the IPM perspective.

  • Always use an irrigation system to direct the water close to plant roots:  Any irrigation system is better than nothing at all, since the goal is to direct the water where the plant roots are. For example, a vegetable garden with soaker hose is better than a garden with flood irrigation that leads to the loss of top soil, nutrients, and chokes the plant roots. Although the use of soaker hose is not the best option for vegetable production, they are often cheap and readily available to the gardeners through the local stores. Today most vegetable producers use drip irrigation system that trickles water to the plant root zone. Sprinkler irrigation can be used for small vegetable plants but the risk of foliar diseases increases greatly along with uneven water application in the late growth stages.
  • Keep the vegetable leaves dry to reduce pathogens and insects:  Overhead or sprinkler irrigation wets the plant foliage that may be favorable for disease development. Splashing water off the plants may also result in the movement of pathogens between closely planted plants. There are certain benefits to overhead irrigation (for example, dislodging aphids from leaves or drowning spider mites) but loss of water to evaporation and risk of disease are greater threats in vegetable production. Use of soaker hose and drip irrigation system (i.e., low-pressure systems) under the plants reduces loss of insecticides applied to the plant foliage. This huge benefit really for organic producers who may use bioinsecticides for pest management. Vegetable field with drip irrigation system also make it possible to inject systemic chemical insecticides through the drip line reducing the need for overhead applications.
  • Use mulch to hide the drip lines or soaker hoses:  It is a good idea to use mulch on the top soil to hide the irrigation system and reduce evaporative loss. Mulch will also retain soil moisture, reduces weed seed germination and soil erosion. In a garden situation, mulches can also absorb excess pesticides and prevent them from wash-off or leaching. A variety of natural mulches are available in the stores today – but first do your homework and check whether they are suitable for your farm or garden. Pay attention to the thickness of the mulch as excessive watering under a thick mulch can be detrimental to the plants and/or harbor insect pests such as cutworms and armyworms.
  • Save on pesticides and energy costs with chemigation: Directed water and insecticidal applications (also known as chemigation) with drip irrigation or other contained systems can drastically reduce need of insecticides and labor costs. Record your garden or farm activities in order to document the effectiveness of your irrigation system. Solve your irrigation challenges with sound logic and common sense. When in doubt, call your nearest extension office for help with designing suitable irrigation and pest management systems so you can enjoy a plentiful harvest.

For further reading on irrigation and IPM:

Home and Urban Garden IPM Slide Chart Available to Gardeners and Urban Farms 

urban farm IPM toolkit1.PNG

A brand new Urban Farm IPM Toolkit is now available for urban farmers and community gardeners. This wheel slide chart has both conventional and organic insecticide listings for nearly 20 different crops. This publication also has listing of common insect pests with images that may help when scouting garden vegetables. Email to get your own copy. Don't forget to visit the Alabama Vegetable IPM website ( for IPM videos and other publications.

Ayanava Majumdar, Extension Entomologist and State SARE Program Coordinator

There are thousands of insects in residential ecosystems, most of which emerge in response to the weather, temperature in particular. Spring weather conditions can change considerably from year to year, so can the time to take action against a certain insect. For centuries, people have used plant phenology (blooms, leaf flush) as nature's signs to set up wasp traps and mend window screens to fend off house flies. Phenology uses the correlation of recurring seasonal plant and insect life cycle stages, rather than calendar date, to predict the activity of pests.

Though the exact dates of emergence of the same species may vary from year to year, pest emergence around homes in Alabama occurs in a very similar order every year. The temperature-dependent biology of insects makes them better in tune with an ever changing climate, than the calendar.

With spring in full swing, live creatures are reviving and coming out looking for food and mates. For home residents, now is the time to act against troublesome spring pests and to pest-proof your home.

Wasps and bees: A variety of bees and wasps always like to challenge unpredictable spring weather, taking advantage of the first blooms to feed after several months without food. Wasps usually do not sting unless they feel threatened. They also do not fly into your face and hair the way honey bees do.

Carpenter bees are among the first early spring adventurers. They tirelessly fly around collecting nectar/pollen from blooming ornamentals and buzzing around your home looking for wood in which to lay their eggs. They do not eat wood, but do severe damage by boring half-inch wide burrows that can extend up to 14 inches into exposed dry wood – such as the siding, the back side of fascia boards, and porch window trim, and porch ceilings. They also bore into decks, fence posts, swing sets, even outdoor furniture. If you had carpenter bees last year, you will likely have them again this year because carpenter bee females prefer to reuse the old galleries to rear the next generation. This behavior is called site-fidelity. Some of you may remember that from 2011-2014, our extension agent team evaluated the carpenter-bee specific traps donated by Mr. Brian Blazer. Two traps from that trial have been left hanging in the corners of the front porch at one site and checked every year. Yearly capture has decreased from >100 to 5 last year. One carpenter bee has been caught this year.


Wasps include hornets, mud daubers, and yellow jackets. They help control other insect populations, but their stings make them unwelcome. They are especially attracted to sweet food and drink. Spring is the time for them to build new nests. Hornets have open structure nests with visible hexagonal cells, often built under the eaves of houses, in attic rafters and other cover areas and resemble an upside down umbrella. Yellow jackets build open nests surrounded by a papery covering and are often found within wall voids and attic or cavities in the ground. Mud daubers construct small mud nests in or around homes, and under open structures. Spring is the time for wasp/bee inspection and nest removal. A little effort and time is sufficient to remove the nests when they are small and only a few wasps to deal with. You may be able to knock it down and dispose it before the queen has a chance to lay eggs. You may also use a can of wasp spray to kill the wasps before removal. Put on protective clothing for this job.

Trapping wasps and bees: If carpenter bees are the only problem, the carpenter bee specific trap should work. If you have a diverse wasp/bee problem and nest removal is not a good option for you, try Rescue TrapStik. We did a 3-year field evaluation of this product and found it worked well. It mainly works for wasps, but is also attractive to kudzu bug adults. The new design of this product has a bird-guard to keep birds away.

Ants: Most ants are opportunistic when it comes to temperature and food. They are active all year with increased activity in the warmer months. Argentine ants are the most common species around homes. They build colonies anywhere that is moist, dark, and undisturbed; in and under plant pots, used railroad ties in landscape, void and cavities of brick, rock, garbage can, etc. Fire ant mounds are popping up now in lawns and flowerbeds. The large black carpenter ants live in rotting or moisture-damaged wood and piles of sawdust-like shaving indicates its presence. Ants are generally around the periphery of a home, but may invade homes for food and refuge on rainy days. Last weekend, we witnessed Argentine ants marching; millions of ants walking about 200 feet! Control practices for Argentine ants begin with locating the colony site and kill them there. Get rid of all potential nesting and food sources around the home. Potted plants should be placed on raised objects and not touching the ground or treated with an insect growth regulator (IGR) underneath the pots. Most of the currently available fire ant baits work very well when applied according to label instruction. Make sure the bait is fresh and less than a year old. The last choice is creating an insecticidal barrier between the perimeter of the home and the rest of the landscape.

Cockroaches: Cockroaches are nasty and a nuisance. They can carry disease-causing pathogens and contaminate household. They also can trigger allergy symptoms in sensitive people. The large cockroaches, including American and smokybrown cockroaches generally live and reproduce outside homes. These large cockroaches may wander into homes but will not usually survive long inside. They are scavengers that love food waste and rotting organic materials. Your first defense is to protect and seal your home's perimeter so that they never make it inside. Baits are proven to be effective in controlling cockroaches.

Seasonal invaders: Spring is the time for seasonal insects invading homes. This group includes ladybugs, kudzu bugs, brown marmorated stink bug, flies, adult carpet beetles, etc. These incidental invaders are bothersome, annoying and a nuisance, thought they don't bite or sting.

Occasional invaders: These include boxelder bugs, centipedes, earwigs, millipedes, pillbugs and sowbugs, silverfish, and spring tails. They are mostly moisture-lovers.

How to fend off spring pests? Spring cleaning tips:

  • Seal up everything:  Insects can squeeze in through any tiny gap, crack, or opening in a wall, siding, around window and door, near gutter and along foundation, even on your roof.  The time you spend sealing up openings is an excellent investment in prevention of invaders later on. 
  • Keep waste around the home cleaned and covered or sealed in tight containers. Promptly clean up pet excrement. Insect pests must eat and drink to live. Any food left out is an invitation for insects seeking a quick "snack" and drink. Leave no clutter inside or outside where pests may hide.
  • Do not bring them in. Many insects are excellent hitchhikers. Inspect what you bring into home. Look closely for insects on or in garden plants or in bags of soil and mulch. Examine paper bags and cardboard boxes for live insects or signs of their presence.
  • Minimize excess moisture and organic matter around your home. Check your home for damp areas that favor bugs. Create unsuitable environments (usually dryer and without many plants and rocks) so they will not want to come near. When watering, it's better to water early in the morning rather than in the evening. The water will soak in and the excess will have a chance to evaporate.
  • Minimize hiding places. Landscape components can affect pest abundance. Clean up leaf litter, mow your lawn regularly, and discard the clippings away from the home.
  • Minimize contact between house and landscape. Trim plant material that touches the outside of the home. Insects can crawl from the soil, up a plant, and easily onto your home.

Xing Ping Hu and Arthur Appel

Department of Entomology and Plant Pathology

 Auburn University, AL 


Soil health is the ability of soil to perform functions that support life on earth. It provides food, fiber, and energy to sustain human life. Soil also protects our natural resources by filtering water and decomposing harmful chemicals.

Properties of a Healthy Soil

  • High organic matter content
  • Optimal nutrients and pH for plant growth
  • Stable aggregates to promote water infiltration
  • Large population of beneficial organisms
  • No compaction layers
  • No contamination

The Role of Soil Organic Matter

Soil consists of four components: minerals, air, water, and organic matter. Organic matter is comprised of carbon-containing compounds from dead and living plant and animal materials. Organic matter performs many functions that support soil heath, such as increasing the amount of plant-available nutrients and water a soil can hold. It also improves soil structure and decreases risk of soil compaction. Soil organic matter is a source of "food" for microorganisms. One handful of soil contains more microorganisms than there are people on earth. These microorganisms in soils are important for recycling nutrients for plant growth, purifying water, and controlling pathogens. Many soils in Alabama are depleted in soil organic matter due to the warm climate, coarse-textured soils, and intensive farming practices historically used in the state. It is important to rebuild soil health to conserve this natural resource for use by future generations. Practices such as reduced tillage and cover cropping can increase organic matter and improve soil health in Alabama.

To read about improving soil health and measuring soil, please see the full article here.


I have been receiving a surprising number of questions on how to control slugs in greenhouses and high tunnels over the past few weeks.  The cooler weather certainly favors them as well as the cloudy weather.  Damage from snails and slugs can resemble that done by insect pests such as caterpillars and wireworms.

Slugs and snails are usually nocturnal so their damage is generally noticed before the pests are actually seen. Slugs and snails leave silvery slime trails on the ground and over the plants. Slugs and snails may consume several times their own body weight each night; damage can be serious within a short time.

Slugs are apparently not repelled by light, but are repelled by rising temperatures. As temperatures rise, slugs crawl down to their hiding places on the soil surface to rest and absorb water through their skin. As temperatures start to fall, slugs actively begin foraging.

Slugs are very sensitive to ambient temperature and can detect temperature changes as gradual as 2°F per hour. Slugs prefer to remain at 62 to 64°F although they lay eggs and develop normally (but slower) at lower temperatures. Development ceases below 41°F. Slugs can withstand slight freezing temperatures although their tendency to take shelter in cold weather protects them from freezing. Slugs try to escape from temperatures higher than 70°F. .

"Beer traps" (filling many shallow containers with beer and scattering them around) certainly work but need to be refilled often to be effective.  You can pick them off but you will need to do it when it is cool and not too sunny since slugs are nocturnal.  Iron phosphate (many trade names such as Sluggo) is labeled for use on many vegetable crops including greenhouse tomatoes and lettuce.  It is highly effective.  Another product, metaldehyde baits have been shown to attract slugs up to 3 feet away. The toxic effects of metaldehyde seem to be due to dehydration as metaldehyde elicits excessive mucus production.  In any case, consult the label prior to intended use.

Joe Kemble

Extension Specialist


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