Showing posts from May, 2019

Undercover Tomatoes: Beating the Beet Leafhopper and Avoiding Curly Top Virus Infection

Southwest Yard & Garden by Dr. Marisa Thompson
Question: I suspect that curly top virus caused half of my tomatoes to wilt and die last year before July, so this year I’ve covered each cage with shade cloth to keep the beet leafhopper out. If wrapping each plant keeps insects out, how do the flowers get pollinated? -Mary T., Belen, NM Answer: Covering tomato plants with shade cloth for most of the growing season (especially early on) is a great way to reduce their exposure to the beet leafhopper (Circulifer tenellus), a tiny, jumping insect that is known to transmit curly top virus (also known as beet curly top virus). Beet curly top virus is known to infect several crops, including (no surprise) beets, tomatoes, peppers, beans, potatoes, spinach, cucurbits (cucumbers, squash, melons, and the like), many ornamentals, and weeds such as Russian thistle (tumbleweed) and mustard (e.g., London rocket). Depending on the host species, infection by this virus causes a range of symptoms, from …

Extrafloral Nectaries are Extraordinary

Southwest Yard & Garden

My nectarine and peach trees have hard pale green ball things near the base of leaves. What are they and are they harmful to my trees?

-Charles M., Albuquerque, NM
Answer: How cool! I’d never heard of anything like this before on trees, but when I searched online, I found that bumps like those located at the leaf base and petiole* of Prunus** species are commonly called “extrafloral nectaries” and are thought to be enticements for beneficial insects. Other plants reported to have extrafloral nectaries that we grow in New Mexico include cucumbers, ash trees, cotton, sunflowers, black locusts, willows, and the houseplants croton, cattleya orchid, and hoya.
Side notes: *A petiole is just a fancy name for the little stalk that connects a leaf to a branch. **Prunus species include the stone fruits (almonds, peaches, nectarines, cherries, apricots, plums, etc.)
In the NMSU Extension Guide H-169 “Using Insectary Plants to Attract and Sustain Beneficial Insect…

Spittlebugs are Here, Have No Fear

Southwest Yard & Garden  by Dr. Marisa Thompson

Spittlebugs are hiding inside white clumps of cottony foam on this autumn sage plant in Los Lunas. Photo credit M. Thompson.

Question: What are these pea-sized globs of white foam all over the stems of my rosemary plant? Should I be concerned? -Leslie H., Belen, NM
Answer: It sounds like you’re describing spittlebugs and I’ve been seeing them all over the place lately too. They’re inhabiting the two autumn sage plants at the front entry of our office at the NMSU Agricultural Science Center at Los Lunas. There are thousands of spittlebug species, some of which are commonly found in New Mexico on a variety of plants, including pines and shrubby junipers.
Dr. Carol Sutherland, NMSU Extension Entomology Specialist and NMDA State Entomologist, explained spittlebugs’ unusual behavior and how they got their name:  “So called because they suck up lots of plant sap, only to poop out the rest of this rather nutrient-poor diet. However, they blow bub…

Aphid Issues Pop Up in Surprising Spots on Urban Trees

Southwest Yard & Garden by Dr. Marisa Thompson
Question: What is causing this white webbing that looks like it’s oozing from old pruning cuts in apple trees?
-Aspen Achen, NMSU Extension Agriculture Agent for De Baca County, Fort Sumner, NM Answer: I had never seen anything like those images of white foamy icing rings around the cut edges where large branches had been removed, so I shared the photos with retired NMSU Extension Horticulture Specialist Dr. Curtis Smith and Joran Viers, City Forester with the City of Albuquerque Parks and Recreation Department. Both responded with a likely culprit: the woolly apple aphid. If so, that white stuff is waxy, filamentous flocculence created by these aphids to make a cozy, protective habitat where they can hide. The tree owner is encouraged to investigate this material—by “investigate,” I mean remove some of the outer gunk to expose possible aphids underneath—and send a sample down to the NMSU Plant Diagnostic Clinic (…

Knowing How Much to Water, Part II: #itsSTILLcomplicated

Southwest Yard & Garden by Dr. Marisa Thompson

Question: How much should I be watering my trees?  -  Multiple Gardeners from All Over NM
Answer (Part 2): In last week’s column, we learned about how the type of soil in your garden affects tree water requirements. Now we will focus on other considerations, such as rates of water movement, tree species, age, canopy size, and seasonal fluctuations in water needs. Plants take water up from the soil through their roots all the way to the leaves where it is released into the air. Transpiration is the process by which a plant loses water, primarily through pores in the leaves called stomata. This is a necessary process that involves the use of about 90% of the water that enters the plant through the roots. The other 10% of the water is used in chemical reactions, like photosynthesis, and in plant tissues. Transpiration is necessary for mineral transport from the soil to the plant tissues, for the cooling of the plant through evaporation, for mov…