- Author: Ben Faber
Implications for tequila growers
Agave are a common sight in Southern California and are frequently used in landscaping for homes, businesses, and in public spaces. You've almost certainly seen agave growing in your neighborhood and may even have some growing yourself. Many varieties of agave are grown in San Diego nurseries to keep pace with the demand for these plants across the state and country. As the climate continues to warm and California becomes increasingly dry, hardy and water-conscious plants like agave will more frequently be used in xeriscaping and as ornamentals. However, there is an almost invisible enemy that threatens many of these agave plants. Greasy streaks and smudges appear on leaves, followed by lesions and plant decline. Sometimes, the entire core of the agave collapses. The plants look sickly and unattractive, dismaying homeowners and nursery growers alike. What is causing this damage? Mites.
Agave mites are a difficult pest to manage and can be a serious problem on multiple types of agave. Being proactive and removing infected plants is currently the best way to protect your agave from mite infestations. Recognizing agave mite symptoms and being ruthless with eliminating plants is key to preventing damage. Research on management options is just beginning and there are still many unknowns, so please contact us if you are having issues with agave mites at your nursery, if you have questions, or if you think there is something we should know about. Stayed tuned for future results and hopefully some better news on how to manage this tiny menace!
- Author: Ben Faber
Anthracnose, Sunblotch, and Armillaria Root Rot
Avocado Trunk Canker and Collar Rot
Avocado Branch Canker (Botryosphaeria)
- Author: Ben Faber
RECOGNIZING NATURAL ENEMIES Proper identification of pests, and distinguishing pests from natural enemies, is essential for effective biological control. Carefully observe the mites and insects on your plants to help discern their activity. For example, some people may mistake syrphid fly larvae for caterpillars. However, syrphid fly larvae are found feeding on aphids and not chewing on the plant itself. If you find mites on your plants, observe them with a good hand lens. Predaceous mites appear more active than plant-feeding species. In comparison with pest mites, predaceous mites are often larger and do not occur in large groups. Consult publications listed in the References to learn more about the specific pests and their natural enemies in your gardens and landscapes. Take unfamiliar organisms you find to your local University of California (UC) Cooperative Extension office, UC Master Gardener Program, or agricultural commissioner office in your county for aid in identification. CONSERVATION: PROTECT NATURAL ENEMIES Preserve existing natural enemies by choosing cultural, mechanical, or selective chemical controls that do not harm beneficial species. Remember, only about 1% of all insects and mites are harmful. Most pests are attacked by multiple species of natural enemies (Table 1), and their conservation is the primary way to successfully use biological control. Judicious (e.g., selective, timing) pesticide use, ant control, and habitat manipulation are key conservation strategies. Ant Control and Honeydew Producers The Argentine ant and certain other ant species are considered pests primarily because they feed on honeydew produced by insects that suck phloem sap, such as aphids, mealybugs, soft scales, psyllids, and whiteflies. Ants protect honeydew producers from predators and parasites that might otherwise control them. Ants sometimes move these honeydew-producing insects from plant to plant (called “farming”). Where natural enemies are present, if ants are controlled, populations of many pests will gradually (over several generations of pests) be reduced as natural enemies become more abundant. Control methods include cultivating soil around ant nests, encircling trunks with ant barriers of sticky material, and applying insecticide baits near plants. See Pest Notes: Ants for more information. Mark Hoddle at UC Riverside is working on a gel formulation to attract ants selectively for their control: http://biocontrol.ucr.edu/hoddle/. Habitat Manipulation Plant a variety of species that flower at different times to provide natural enemies with nectar, pollen, and shelter throughout the growing season. The adult stage of many insects with predaceous larvae (such as green lacewings and syrphid flies) and many adult parasites feed only on pollen and nectar. Even if pests are abundant for the predaceous and parasitic stages, many beneficials will do poorly unless flowering and nectar-producing plants are available to supplement their diet. To retain predators and parasites, grow diverse plant species well adapted to the local conditions and that tolerate low populations of plant-feeding insects and mites so that some food is always available. Other cultural controls that can help natural enemies include reducing dust and properly fertilizing and irrigating. Dust can interfere with natural enemies and may cause outbreaks of pests such as spider mites. Reduce dust by planting ground covers and windbreaks and hosing off small plants that become excessively covered with dust. Avoid excess fertilization and irrigation, which can cause phloem-feeding pests, such as aphids, to reproduce more rapidly than natural enemies can provide control. REFERENCES Dreistadt, S.H., M.L. Flint, and J.K. Clark. 2004. Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide. 2nd ed. Oakland: Univ. Calif. Agric. Nat. Res. Publ. 3359. Flint, M.L. and S.H. Dreistadt. 1998. Natural Enemies Handbook: The Illustrated Guide to Biological Pest Control. Oakland: Univ. Calif. Div. Agric. Nat. Res. Publ. 3386. Rust, M.K. and D.-H. Choe. 2012. Pest Notes: Ants. Oakland: Univ. Calif. Agric. Nat. Res. Publ. 7411.
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NATURAL ENEMIES |
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PESTS |
Lacewings |
Lady beetles |
Parasitic flies |
Parasitic wasps |
Predatory mites |
Other Groups and Examples |
aphids |
X |
X |
|
X |
|
entomopathogenic fungi, soldier beetles, syrphid fly larvae |
carpenterworm, clearwing moth larvae |
|
|
|
X |
|
entomopathogenic nematodes |
caterpillars (e.g., California oakworm) |
X |
|
X |
X |
|
Bacillus thuringiensis, birds, entomopathogenic fungi and viruses, predaceous bugs and wasps,Trichogramma spp. (egg parasitic wasps), spiders |
cottony cushion scale |
|
X |
X |
|
|
Cryptochaetum iceryae (parasitic fly), vedalia beetle |
elm leaf beetle |
|
|
X |
X |
|
Erynniopsis antennata (parasitic fly),Oomyzus (=Tetrastichus) spp. (parasitic wasps) |
eucalyptus longhorned borers |
|
|
|
X |
|
Avetianella longoi (egg parasitic wasp) |
eucalyptus redgum lerp psyllid |
|
|
|
X |
|
Psyllaephagus bliteus (parasitic wasp) |
giant whitefly |
X |
X |
|
X |
|
Encarsia hispida, Encarsia noyesi, Entedononecremnus krauteri, andIdioporus affinis (parasitic wasp), syrphid fly larvae |
glassy-winged sharpshooter |
X |
|
|
X |
|
assassin bugs, Gonatocerus spp. (egg parasitic wasps), spiders |
lace bugs |
X |
X |
|
X |
|
assassin bugs and pirate bugs, spiders |
mealybugs |
X |
X |
|
X |
|
mealybug destroyer lady beetle |
mosquitoes |
|
|
|
|
|
Bacillus thuringiensis spp. israelensis, mosquito-eating fish |
psyllids |
X |
X |
|
X |
|
pirate bugs |
scales |
X |
X |
|
X |
X |
Aphytis, Coccophagus, Encarsia, andMetaphycus spp. parasitic wasps |
slugs, snails |
|
|
X |
|
|
Rumina decollata (predatory snail), predaceous ground beetles, birds, snakes, toads, and other vertebrates |
spider mites |
X |
X |
|
|
X |
bigeyed bugs and minute pirate bugs,Feltiella spp. (predatory cecidomyiid fly larvae), sixspotted thrips, Stethorus picipes (spider mite destroyer lady beetle), predatory mites |
thrips |
X |
|
|
X |
X |
minute pirate bugs, predatory thrips |
weevils, root or soil-dwelling |
|
|
|
X |
|
Steinernema carpocapsae andHeterorhabditis bacteriophora(entomopathogenic nematodes) |
whiteflies |
X |
X |
|
X |
|
bigeyed bugs and minute pirate bugs,Cales, Encarsia, and Eretmocerus spp. parasitic wasps, spiders |
Predatory mite going after citrus red mite
/table>- Author: Ben Faber
- Author: Ben Faber
Bob Hill, a local Ventura PCA, saw an interesting mite he had never seen before and asked if I could id it. Well, I sent it in to Mark Hoddle and UCR and he turned it over to his student Ricky Lara to id it. And this is what he says:
I started finding this type of mite infrequently in 2011, when I was sampling foliage in avocado orchards. Although seldom seen, they have a wide geographic distribution on avocado. I found them in Cambria (SLO), Santa Rosa Valley (Ventura County) and Irvine (Orange County). At the time I narrowed down the mite family to Winterschmidtiidae. I have to double check, but I believe their feeding habit is listed as fungivorous (The Manual of Acarology). They might feed directly on plant material too (no fungus on the avocado leaves I sampled) but no one has really studied them. I tried rearing them in the lab (without other mites as a food source, only pollen) but the colony only lasted for a couple of months. On avocado I have seen these mites at the leaf-vein junctions. This probably provides a natural home ("domatia") for them as it does for other mites (e.g. phytoseiids, tydeids, stigmaeids). On lemons, the calyx structure probably serves the same ecological function for these mites.
The tydeid mites are what I call the "tidy mites" since their basic function is to run around and clean up leaves, although there are some predatory and scavenging members of the family This little guy is just one of the many tidy mites found out there and its recent appearance is just a reflection of the weather/climate we have this time.
The red circled mite is the one we are talking about here. The structures next to it are some egg cases of another animal. The red dots are called opisthonotal glands which produce pheromones, the purpose of which is not clear.