Desert Blooms

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 ...

Southwest Yard & Garden   Extrafloral nectaries on the petioles of these cherry tree leaves look like rosy eggs. Photo credit M. Thompson. Question: 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 t...

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 ...

Southwest Yard & Garden by Dr. Marisa Thompson White masses found on the edges of old pruning cuts on this apple tree may be evidence of woolly apple aphid populations. Photo credit A. Achen. 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 w oolly apple aphid. If so, that white stuff is waxy, filamentous flocculence created by these aphids to make a cozy, protective habitat where they can hi...

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% ...