- Prepared by: UC Integrated Pest Management Program
If you've noticed tiny, dark insects flying around your houseplants, you likely have fungus gnats. These tiny flies can be a nuisance indoors and may also damage your plants.
Fungus gnats lay their eggs in moist soil and their larvae feed on plant roots and decaying organic matter. Because of this, the key to managing fungus gnats is to let the soil dry out in between watering and don't overwater plants. Water plants from the bottom using saucers under pots. This keeps the top of the soil dry, discouraging fungus gnats.
Sticky traps can be placed in pots or near plants to catch fungus gnat adults. This is also a great way to monitor for fungus gnats. Pesticides, including several biological pesticides like Bacillus thuringiensis subspecies israelensis (Bti), are available to control fungus gnats. However, the best way to control fungus gnats is by simply adjusting watering practices.
To learn more about fungus gnats and their management, visit Pest Notes: Fungus Gnats.
This article first appeared in the UC Integrated Pest Management Program's Pests in the Urban Landscape blog.
- Prepared by: Terry Lewis
Tasks
- Adjust watering systems as weather cools.
- Remove and dispose of any fruit and nuts that cling to the tree.
- To discourage spider mites, spray hedges and shrubs with water to clean them and keep them free of dust.
- Water citrus, being careful not to overwater. Continuously wet soil risks root rot.
Pruning
- Do not apply any treatments to pruning cuts or other wounds because these materials are ineffective (and often detrimental).
- Deadhead and shape rosebushes to promote a final fall bloom.
Fertilizing
- Wait two weeks after planting new flowers and vegetables before feeding with organic or complete fertilizer.
- Add bulb fertilizer to planting hole before planting bulbs.
Planting
- This is the best time to plant shrubs and groundcovers.
- Groundcovers: Carpet bugle (Ajuga), Germander (Teucrium chamaedrys ‘Nanum').
- Perennials: Cyclamen, French tarragon (Artemisia dracunculus), cranesbill (Geranium).
- Before planting winter vegetables, turn a generous amount of compost into the vegetable bed.
- Fruits and vegetables: garlic, onion sets, lettuce, parsley.
- Trees, shrubs, vines: Acacia baileyana, strawberry tree (Arbutus ‘Marina'), hawthorn (Crataegus), sago palm (Cycas), desert willow (Chilopsis linearis).
Enjoy now
- Annuals and perennials: vinca (Catharanthus), chrysanthemum, dianthus, coneflower (Echinacea), globe amaranth (Gomphrena).
- Bulbs, corms, tubers: dahlia.
- Trees, shrubs, vines: pineapple guava (Feijoa), morning glory (Ipomoea), crape myrtle (Lagerstroemia).
- Fruits and vegetables: almonds, lettuce, melon, nectarines, persimmon.
- Fall color: goldenrain tree (Koelreuteria), sweet gum (Liquidambar styraciflua).
Things to ponder
- Do not replace vinca with pansies in the same bed, due to a soil borne fungal root rot that affects these plants.
It's Autumn! As we shift to cooler weather, take time to evaluate your garden's damage and stress caused by this summer's extreme heat. This is the perfect time to devise long-term cooling and shading strategies to reduce sun and heat damage in the future.
Write down your observations, keeping in mind the damaged plant species, location in the garden, and daily hours of exposure to sunlight and shade, especially during the summer months. Be sure to note whether the plant receives hot afternoon sun (western/southern exposure) rather than a kinder eastern morning sun exposure. Note any nearby hardscaping, decorative rocks, pathways, concrete, or buildings that reflect heat and sunlight or radiate heat overnight. Take time to analyze soil condition, moisture, watering system coverage, mulch, and any other directly involved factors.
Armed with all your information, ask the following question for each affected plant: is the plant species the right match for its location in terms of summer sunlight? While it's heartbreaking to accept, sometimes the plant isn't suited to our extreme heat conditions, no matter what we do to protect it. A gardener must weigh the time and effort required to safeguard a mismatched plant in our environment. The payoff might not be worth it.
More often, the plant will grow well in our area when relocated to another spot that provides a more appropriate microenvironment. Research the best time to transplant the particular plant species and follow the instructions accordingly. Be mindful of the sun and shade conditions in the plant's new location and be prepared to incorporate some of the following suggestions to protect your plant, even in its improved location.
If the plant can't be relocated, consider incorporating seasonal landscaping solutions. Plant taller, more sun-tolerant annuals or biennials like hollyhocks and sunflowers that cast shade to protect a shorter plant during the harsh summer months. Staking these taller plants may be necessary. A perennial hedge, situated to provide shade during the afternoons, is a longer-term solution.
Dark shade cloth, available in rolls, will also help, but for less unsightly long-term solutions, consider more attractive shade cloth awnings. There are many shapes and colors available; choose a knitted screening cloth with a 30-60% density rating. Permanent, buried concrete footings can be established to hold removable poles or supports that elevate the shade cloth. Even better, cable systems attached to permanent structures by hooks and turnbuckles are excellent ways to create an adequately elevated, taut cover. Build as much flexibility into your shade cloth system as possible so it can easily be removed after the summer to allow winter light in.
Another visually attractive solution combines annual plantings with hardscaping design. Interlace your landscaping with strategically placed lattice panels or other decorative open fencing tall enough to provide shade for low shrubs, ornamentals, and roses. Fence placement should focus on reducing your garden's exposure to the hot south or western sun. Plant fast-growing annual vines to temporarily climb on the fencing to add visual interest and, of course, increase shading possibilities.
Trees, especially quick-growing, tall, narrow trees, are another longer-term way to provide shade in extreme heat. Thoughtful analysis, planning and selection is essential when planting trees to establish a permanent break from hot afternoon sun. Pruning to properly shape and manage tree height may be necessary.
Concrete paths and driveways often increase daytime reflective light and temperatures and radiate excessive overnight heat near plants that need to cool down. Removing the concrete and replacing it with gravel is an option. Any gravel materials will store heat during the day and radiate it back at night but gravel can raise humidity if the underlying soil is moist, possibly helping to cool nearby areas[O1] . Extending mulch onto the concrete can be a short-term alternative. As is often the case, adding deep mulch throughout your landscape is a very beneficial way to reduce heat and dryness experienced by a plant's surface roots.
Adding an outdoor fountain or other type of water feature is another way to cool things down. As the mist from a fountain evaporates, it cools the surrounding air. The increased humidity from mist helps heat-stressed plants and even aids in flower retention. Misting systems are a good alternative if a water feature is out of the question. Placing time-controlled mist emitters high in trees and along rooflines of garden buildings can bring extreme temperatures down quite a bit.
When adopting these cooling solutions, be open to flexibility and possibility. Future extreme heat events, each unique, will require you to adapt your landscape planning to weather changes. If something doesn't work out, try a different strategy. Eventually, your garden will be a happier, and hopefully cooler, oasis.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu or leave a phone message on our Hotline at 530-552-5812. To speak to a Master Gardener about a gardening issue, or to drop by the MG office during Hotline hours, see the most current information on our Ask Us section of our website.
- Author: Kathy Keatley Garvey
YSP is a six-week summer residential program that introduces several dozen high-achieving high school students to original research within the fields of biological, agricultural, environmental, or the natural sciences.
The lab of nematologist Shahid Siddique, associate professor, UC Davis Department of Entomology and Nematology, mentored Anderson Van Wang, a 17-year-old senior at California City High School, Kern County, and Mason Walline, now 18, and a senior at Harvard-Westlake School, Los Angeles.
Anderson worked with doctoral student Veronica Casey of the Siddique lab to investigate the effects of bacterial supernatant to plant parasitic nematodes. Walline worked with Ching-Jung Lin, a doctoral student in the Siddique lab and the lab of Professor Gitta Coaker, Department to Plant Pathology, to transiently express nematode proteins in the plant system.
Also mentoring them were Siddique and lab members Bardo Castro Esparza, a postdoctoral fellow; and Alison Blundell, a doctoral candidate.
Each scholar receives five units of University Group Study Credit. All work is graded. Not only do they engage in university-level course work, attend lectures, and work on their projects, but they experience “the climate and culture of living and learning on a university campus,” according to YSP director Megan Bettis.
Mason won second-place honors in the research competition, the "YSP Summer Slam" (Elevator Pitch or short-version), competing with some 35 other students. His topic: “Advancing Transient Nematode Peptide Expression: A Pathway to Co-Immunoprecipitation Optimization." Said Lin: "He delivered a compelling two-minute presentation with a single slide. His expertise and professionalism were evident, and he was awarded second-place among the six finalists."
Neither plans a career as a nematologist, but what an amazing program and what an amazing experience.
“Working in Dr. Shahid Siddique's lab was an absolutely amazing experience," Anderson said.
“The lab environment was very high energy and upbeat," said Mason. "I'm so glad I was a temporary part of such a strong and inclusive community.”
And they learned a lot about nematodes.
Siddique defines plant-parasitic nematodes as "destructive pests causing losses of billions of dollars annually. Economic, health, and environmental considerations make natural host plant resistance a preferred strategy for nematode control, but there are limitations to this approach. In many cases, the resistance conferred by resistance genes is partial, and some of the nematodes are able to survive. Similarly, nematode resistance genes are often effective against only one or a few species, whereas plants are exposed to several pathogens in the field. Another concern is the emergence of pathotypes that can overcome resistance. In view of all these limitations, it is important to identify additional mechanisms and tools that can be used to develop novel and sustainable approaches to the management of nematodes."
The 2025 YSP summer program is set June 22-Aug. 2, with applications opening Jan. 15. High school students can apply at https://ysp-app.ucdavis.edu/.
- Author: Bob Niklewicz, MG at the Fuller Park Rose Garden
The October Master Gardener's Rose Cycle chart (https://napamg.ucanr.edu/files/254549.pdf) has us continuing to deadhead and removing infected leaves that show yellowing, black spots, browning edges and/or have pests lurking among the blossoms and stems. The blossoms are coming slower and in fewer numbers. Enjoy what is out there for the next couple of months.
Many of our bushes have suffered from the elevated heat, and diminished watering. Leaves have turned brown, look wilted and/or just fell off to preserve the moisture in the bush. Many leaves look dull and are no longer glossy. Don't be surprised or feel bad that the rose garden has the same problems you have in your yard. This too, is part of the rose cycle and nature.
Now is the time to handle the heat issues and to watch out for signs of delayed heat stress that caused the leaves to yellow or be susceptible to black spots and pests. Pick off those infected leaves that haven't fallen off the branches as well as those that are on the ground and put them in the city compost bins to reduce the spread of fungus. Remember to sterilize your pruners after each bush to reduce the spread of the black spots.
Keep watering the bushes a couple of times a week with about a gallon per plant during these cooler days. If we do get another hot period, add another day of watering.
The bushes will be starting to store nutrients in the roots for the winter. The last dose of organic fertilizer should have already been done, but if it hasn't, follow the dosing instructions on the packages and do it now.
ROSE of the MONTH: 'Firefighter'
The 'Firefighter' is a very popular rose in our garden. It is a hybrid tea with wonderful full and dark red blooms. It is great for cuttings with a wonderful fragrance. Though it is supposed to be thornless, it still gets some. It is disease resistant and a rose with a classic look.
It can grow to 6' tall if you let it and easily 3-4' across. It does great in our Zone 9 climate.
Remember when pruning to toss that plant debris into your city compost bin and not your own compost pile. The Napa City compost center produces higher temperatures to destroy the spores while your backyard pile will not do so. When it comes time to add mulch, consider getting it from the Napa Recycling & Composting Facility.
If you have questions about the Fuller Park Rose Garden and the Master Gardeners (MGs) who maintain that Rose Garden, the MGs are usually in the garden the first Sunday and third Thursday of each month between 10:00 and 12:00, weather permitting.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions. You can also go to our Master Gardener website: napamg.ucanr.edu for more details.
Photos by Bob Niklewicz