Members of the Phyllophaga genus are found throughout Florida and most of North America. One of them is the May/June beetle. Adults are most active during the rainy season. So in parts of the country where the wetter months are May or June, the common name of this insect makes common sense. But, when an area experiences extra rain earlier in the spring, the May/June beetle may emerge from the ground in March or April. That is what has happened in the western Panhandle this spring. May/June beetles have been leaving the soil and flying to the lights of people’s homes.
The life cycle of these beetles varies from one to four years. Eggs are laid in soil each spring by females. In 3 to 4 weeks, small grubs (larvae) hatch from eggs and develop through three stages (instars), with the first two stages lasting about 3 weeks. The larvae will move closer to the surface and back deeper in the soil as the soil temperature changes. While close to the surface, larvae feed on grass roots about one inch below the soil surface. Damaged grass turns brown and increases in size over time. Heavy infested turf feels spongy and moves when walked upon. The last larval stage remains in the soil from the fall through spring. The cool soil temperatures drive the larvae deeper in the soil where they remain relatively inactive. Typically, on the third year, white grubs pupate 3 to 6 inches deep in the soil and emerge as adults.
Larvae, called grubs, vary in length from ¾ to 1 ¾ inches depending on the stages. Grubs are white with a C-shaped body with a brown head and three pairs of legs near the head. Adults have ½ to 1 inch long, shiny bodies that are dark yellow to brownish-red in color. Adults do feed on the foliage of several species of ornamental plants, but the damage is typically only aesthetic; not causing long-term harm.
Monitoring of and managing emerging adults can help with deciding on the need for insecticide control for the grubs. To catch and remove adult beetles, place white buckets containing soapy water near plants that have chew marks or areas with lights at night. Leave it overnight. The beetles can easily be disposed of the next day. If there are more than 12 in the bucket be prepared to monitor the lawn for grubs. Extra rain or frequent irrigation during the adult flight time may attract more egg-laying females.
To inspect for grubs, turn over sod to a depth of at least two-inches. If there are an average of three or more per square foot, an insecticide treatment may be needed. To confirm that they are May/June beetles inspect the darkened rear of the grub. Locate the anal slit. It should be Y-shaped with two rows of parallel bristles that point toward each other. This is referred to as the raster pattern. All grub species can be identified using their unique “butt” features.
The most effective time to control this pest is summer or early fall when the larvae are small. Remove as much thatch as possible before applying an insecticide. Spot treat the off-colored area plus the surrounding 10 feet with products containing imidacloprid or halofenozide in early summer. Follow up in the fall with insecticides such as trichlorfon, bifenthrin or carbaryl if grubs persist.
Recently, I received a call about a garden not producing the way it used to. After speaking with the homeowner, I decided to take a visit to see what was going on. On my visit, I could see that the tomatoes were stunted, yellow and wilting, the squash plants were flowering but not setting fruit, and the okra was stunted. After digging up some of the sick plants and examining the roots, the problem was as clear as day…root-knot nematodes.
Galls on roots from root-knot nematodes
Root-knot nematodes are microscopic, unsegmented roundworms that live in the soil and feed on the roots of many common garden plants. Some of the most commonly damaged crops are tomatoes, potatoes, okra, beans, peppers, eggplants, peas, cucumbers, carrots, field peas, squash, and melons. Root-knot nematodes enter the root and feed, causing knots or galls to form. These galls are easily recognizable on the roots. If you’re inspecting the roots of beans or peas, be careful not to confuse nematode galls with the nitrogen-fixing nodules that are a normal part of the root system. As the nematodes feed, the root system of the plant becomes damaged and the plant is unable to take up water and nutrients from the soil. As a result, the plant may show symptoms of stunting, yellowing, and wilting.
What can I do about nematodes?
There are currently no nematicides labeled for use in the home garden but the best means of root-knot nematode management involves using a combination of strategies that make your garden less susceptible to attack.
Grow Resistant Varieties
Some varieties of crops are resistant to root-knot nematodes. This means is that a particular nematode can’t reproduce on the plant roots. When buying seed, read the variety label. The label may have ‘VFN’ written in capital letters. These letters indicate that the variety has resistance to certain diseases: V = Verticillium wilt; F = Fusarium wilt; and N = root-knot nematode. It’s best to use resistant varieties when root-knot nematodes are present.
Tomato plant showing signs of nematode damage – yellowing and wilting.
Sanitation
If you suspect you may have a nematode problem, be sure not to move soil or infected plant roots from an infected area to a clean area. Nematodes can easily be spread by garden tillers, hand tools, etc. so be sure to disinfect all equipment after use in problem areas.
Infected roots left in the soil can continue to harbor nematodes. After the crop is harvested, pull up the roots and get rid of them. Tilling the soil can kill nematodes by exposing them to sunlight.
Cover crops and Crop Rotation
Cover crops and crop rotation isn’t just a concept for farmers…gardeners need to implement the same practices! While this may take some planning, it is the most effective way to reduce pests and diseases.
Cover crops are crops that are not harvested and are typically planted between harvestable crops. They help improve soil quality, prevent soil erosion, and help control pests and diseases. Selecting cover crops that aren’t susceptible to root-knot nematode attack is key. When growing a cover crop that nematodes can’t reproduce on, populations should decline or not build up to begin with. Grain sorghum and millet can be planted as a summer cover crop and rye in the winter. French marigolds have been shown to reduce nematode populations as well.
Another simple way to manage root-knot nematodes is by crop rotation. Crop rotation is the practice of not growing crops that are susceptible to nematode attack, in the same spot for more than one year. Crops that aren’t susceptible to attack are cool season crops in the cabbage family such as broccoli, cauliflower, Brussels sprouts, collards and kale.
Root-knot nematodes can wreck havoc on a garden so it’s important to take the necessary precautions to avoid them. It may require planning and patience but it will be worth it in the long run!
For more information on this topic, use the links to the following publications:
Hydrangea leaf spot disease Photo credit: Larry Williams
It is not uncommon to see leaf spots on your hydrangeas during late summer and fall.
These spots are caused by a number of fungal diseases. Plant fungi and wet weather go hand-in-hand. Florida’s high humidity, heavy dews and frequent rains during spring and summer provide perfect conditions to allow fungal diseases to flourish. Bacterial leaf spots can be part of this foliage disease mix, too.
Common foliage diseases seen on hydrangeas this time of year include Phyllosticta leaf spot, Target leaf spot, Bacterial leaf spot, Botrytis and Cercospora leaf spot.
These foliage diseases are the norm rather than the exception as we move into the wet summer months and on into fall. As a matter of fact, you would be hard-pressed to find any hydrangea in our area without some evidence of infection now.
This late in the year it is more of a “grin and bear it” problem. In other words, it’s too late to do much about the fact that your hydrangea plant has leaves covered in ugly spots. By now many of the infected leaves are turning brown, withering and dropping prematurely from the plant.
Cercospora leaf spot is one of the most common foliage diseases of hydrangeas. Along with most of the leaf spot diseases, it begins as small dark-colored specks on the leaves. The small specks generally go unnoticed. But as the spots continue to slowly enlarge, mostly maintaining a circular shape, they become more obvious. With heavy infection, individual spots can coalesce forming larger irregular shaped brown areas on individual leaves. The individual spots may have a purplish halo with gray center.
There are some fungicides that can help prevent these leaf spots. But you’d have to begin treatment early in spring before any leaf spots exist and spray the plant every 10 to 14 days during favorable disease development (humid, rainy weather), which is pretty much our spring and summer months. These types of diseases are prevented, not cured. That’s the “grin and bear it” part of waiting until now.
The fungus survives on infected leaves. So, the best thing to do now is to remove and dispose of infected leaves. Also, be careful to not wet the leaves when irrigating the plants during the growing season.
New leaves of spring should be spot/disease free as they emerge. But the cycle of life for these leaf spot diseases will again result in spotted/diseased leaves on your hydrangeas next summer and fall without persistent treatment.
The good news is that these leaf spot diseases normally do not cause permanent/long-term damage for hydrangeas. They just make the plant look ugly.
On June 6th, we held an Invasive Species Workshop: Air Potato Challenge and Species Awareness day at the UF/IFAS Extension Office in Panama City. Over 700 air potato leaf beetles were distributed to more than 30 sites in Northwest Florida by citizen scientists to help manage the invasive air potato vine!
Rick O’Connor, UF/IFAS Extension, tells us about the ball python, a potential invasive species. Rick also provides an overview of keeping pythons and other snakes as pets. http://edis.ifas.ufl.edu/pdffiles/UW/UW34100.pdf
Holli Nichols, FWC, tells us about the Wildlife Assistance program for homeowners and property owners. Holli helps out find solutions for negative encounters with Wildlife. Most problems are easily solved and she provides a few tips. Holli also tells us about the FWC Pet Amnesty Program for Exotic Pets. Watch to learn more. http://myfwc.com/conse…/you-conserve/assistnuisance-wildlife
Kira Burdeshaw, SCN of NW FL, shows off the tokay gecko we found at the Extension office on the front porch earlier in May. The Gecko moved in with Kira and her other reptiles at the Science and Discovery Center.
…http://myfwc.com/wildlifeha…/nonnatives/reptiles/tokay-gecko
Derek Fussell with FWC Invasive Aquatic Plant Management talks about Giant Salvinia, a species of concern for Deer Point Lake in Bay County, Florida. Here’s a link to a story about the discovery of giant salvinia in Bay County from 2016 https://nwdistrict.ifas.ufl.edu/…/nisaw-2016-working…
Derek Fussell shares a behind the scene’s view of their new boat for controling aquatic plants in Bay County and Northwest Florida. We will visit with Derek and Jamie later and show some of the aquatic invasives they work to control everyday!
Over the last month or so, home gardeners and commercial growers alike have noticed what look to be large dust particles floating through the air. It’s probably not uncommon to have inhaled a few or even a few hundred of these mysterious particles. Most likely, these “particles” aren’t dust at all but whiteflies instead. Whiteflies are small (less than a tenth of an inch long), white, soft-bodied insects. They aren’t flies but are considered ‘true bugs’ by entomologists. The most common whitefly species in Northwest Florida is the silverleaf whitefly, also known as the sweetpotato whitefly. Whitefly numbers have exploded exponentially this year because of last years’ mild winter. These irksome insects feed on a variety of annuals, shrubs, vegetables and trees.
Magnified whitefly adults and eggs. Photo Credit: James Castner, University of Florida/IFAS.
Whiteflies typically feed on the underside of leaves. Initially, disturbed leaves will become pale in color, then a sticky substance may develop on the surface of the leaves. This sticky substance is called honeydew. Honeydew is actually a sugary substance excreted by the whiteflies as part of their elimination process, similar to what aphids and scale insects produce. After honeydew is deposited, sooty mold develops to feed on this readily available sugar source. Sooty mold is a fungus that forms a gray to black colored coating on plant leaves. It normally grows on leaves that were previously covered with honeydew. Sooty mold hinders the ability of leaves to absorb light and ultimately limits photosynthesis.
Pale squash leaves due to feeding from whiteflies. Photo Credit: University of Florida/IFAS.
So what should be done to control whiteflies? It depends on what is being grown. If whiteflies are present, the role of beneficial insects should be taken into consideration. Plenty of predatory insects such as lady bugs and green lacewings are around to feed on whiteflies. In fact, leaving the whiteflies alone on your trees and shrubs will attract more predatory insects. Below are some whitefly control methods that produce minimal damage to beneficial insect populations.
Whitefly Control in Vegetables
Sticky Traps – Yellow sticky traps are a good way to monitor whitefly populations and can help determine when insecticide application is appropriate.
Insecticidal Soaps – Insecticidal soaps are usually applied as a 1 to 2 percent solution (2½ to 5 tablespoons per gallon of water). It is important to follow the application directions on the label. Insecticidal soap should be applied in the evening, when the sun is low in the sky and the temperature is below 85°F. Some insecticidal soaps available at local lawn and garden centers include: Bonide Insecticidal Soap, Bonide Insecticidal Soap, and Bayer Advanced Natria Insecticidal Soap.
Horticultural Oils – Horticultural oils should be handled like insecticidal soaps. Like the soaps, they should be applied in the evening. Some horticultural oils available at local lawn and garden centers include: Bonide All Seasons Spray Oil, Southern Ag Parafine Oil, and Garden Safe Neem Oil.
Other Insecticides – Harsher chemicals are not recommended for the home gardener, because whiteflies have become resistant to most products on the market. Use of broad spectrum insecticides may also contribute to an increase in whitefly populations because they kill beneficial predatory insects.
Hopefully winter will be cooler this year and the profuse whitefly population will be knocked back. Until then, we wish all home gardeners the best of luck with fall gardening!
Larvae, called grubs, vary in length from ¾ to 1 ¾ inches depending on the stages. Grubs are white with a C-shaped body with a brown head and three pairs of legs near the head. Adults have ½ to 1 inch long, shiny bodies that are dark yellow to brownish-red in color. Adults do feed on the foliage of several species of ornamental plants, but the damage is typically only aesthetic; not causing long-term harm.
On June 6th, we held an Invasive Species Workshop: Air Potato Challenge and Species Awareness day at the UF/IFAS Extension Office in Panama City. Over 700 air potato leaf beetles were distributed to more than 30 sites in Northwest Florida by citizen scientists to help manage the invasive air potato vine!
