A green sweat bee, a native pollinator. Photo: Lee Gresham, Metairie, LA
Lee sent an email to identify a pollinator in his garden, “Good morning, I was outside looking at my flowers this morning and noticed what seemed to be a green bee in my yellow purslane. Not sure if it might be an orchid bee, or some kind of green hornet. Its legs were covered in clumps of pollen. [Do you have] any idea? See…picture below. This was in Metairie, LA near [Lake Ponchartrain].”AHA thought that Lee saw a green sweat bee and consulted with Victoria Bayless, Curator, Louisiana State Arthropod Museum, to help with the identification. She affirmed the identification, “Yes, good call, green sweat bee. The striped one I think. Agapostemon sp. We have a couple of species.” This bee is a native, solitary, ground-nesting insect. It will visit the following flowering plants: sunflowers, asters, morning-glories, pumpkins and their relatives, legumes, fringe tree, evening-primroses, irises, roses, and other plants. Long Leggedy Beasties blog shares this caution, “Sweat bees can sting, but generally are not particularly aggressive unless handled roughly. Stings, if they do occur, are relatively minor.”
Suspected rose rosette disease, a viral plant disease. Photo: Jamie Lopez, Bossier Parish.
Jamie of Bossier Parish sent an email asking about her distressed roses, “Attached are a few pics of my roses. I pulled a few last spring that had the same thing and replanted in the fall. Can you tell from the pics what this is? I have an entire row of roses in a retaining wall bed, so I am hoping to prevent it from spreading through all the roses.”AHA suspected that Jamie has rose rosette disease (RRD), a viral plant disease. Dr. Raj Singh, the AgCenter’s Plant Doctor, wrote a factsheet, Rose Rosette Disease, in which he writes about the control of RRD, “Management of rose rosette disease in infected roses is not possible. Once a rose is infected, there is no cure.Several precautions can be taken, however, to avoid introduction of the disease or to reduce its spread from infected to healthy roses. Remove infected roses completely, including roots. New growth from infected roots may serve as a source of the virus. Dispose of infected roses immediately by burning. If burning is not feasible, bag the infected roses before removal.
The wild multiflora rose is highly susceptible to rose rosette disease and eriophyid mites and may serve as a source for both the virus and the mites. Remove symptomatic multiflora roses that exist in areas close to the cultivated roses.Also, start with disease-free, healthy roses and inspect for any rose rosette disease symptoms before purchasing roses. Properly space out the new roses to avoid mites crawling from one plant to another. Clean tools and other equipment used for pruning.
An integrated management of eriophyid mites, including miticides along with cultural practices, may reduce the population of mites and thus the potential spread of Rose rosette disease.”
Clemson Cooperative Extension website discusses how to treat mites on roses, “A strong spray of water is a non-chemical control option that removes eggs, larvae (six-legged immature stage), nymphs (eight-legged immature mites), and adult mites. Be sure to spray the lower surfaces of leaves and repeat as needed. This method is most effective with light infestations, as seen with early detection. An important advantage of this control method is that populations of natural enemies are not harmed.
Insecticidal soaps and horticultural oils are effective control options for spider mites, and they are essentially nontoxic to humans, wildlife, and pets, and only minimally toxic to beneficial predators. Good coverage is critical to ensure contact with the pest when using these products, and reapplication may be needed as determined by follow-up monitoring for the pest. Foliar injury from soaps and oils may occur on plants under drought stress. Water the plants well before spraying. Do not spray with soaps or oils if the temperature exceeds 85 °F, and always spray in the evening to slow the drying time of the soap or oil. Sulfur sprays can also control spider mites. Do not spray if the daily temperatures exceed 85 °F, and do not spray sulfur on plants within 30 days of a horticultural oil spray.
When growing roses, the use of broad-spectrum insecticides should be avoided as much as possible, as these products can kill off natural enemies that help keep spider mite populations in check. Also, avoid pesticides that claim to “suppress” mites as they tend to be weak miticides. When stronger chemical control is needed, the following insecticides/miticides are available in homeowner size packaging: tau-fluvalinate or bifenthrin sprays.”
Queen Anne's Lace or wild carrot flower. Photo: Susan Caldwell, home gardener.
Susan was concerned about a toxic plant in her garden, “I have several stalks of a weed growing in my flower beds and need to know if it is poison hemlock before I try to remove it. I do not like to use chemicals so when I remove weeds from the beds, I either pull or dig them out but do not want to remove these weeds until I find out if it is safe to handle them.”AHA checked with an AgCenter colleague who confirmed that Susan has Queen Anne’s lace or wild carrot. A website, www.inaturalist.org , warns, “ skin contact with the foliage of Daucus carota[wild carrot], especially wet foliage, can cause skin irritation in some people.” However, wild carrot is a good companion plant because it “ is also documented to boost tomato plant production when kept nearby, and it can provide a microclimate of cooler, moister air for lettuce, when intercropped with it.”
If you want to contact Roots, Shoots, Fruits, and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337.464.7006 or khawkins@agcenter.lsu.edu .
“Before you buy or use an insecticide product, first read the label, and strictly follow label recommendations. Mention of trade names or commercial products in this article is for informational purposes only and does not constitute endorsement by Louisiana State University AgCenter.”
“This work has been supported, in part, by the USDA National Institute of Food and Agriculture, Renewable Resources Extension Act Award, Accession Number 1011417.”