Posts Tagged: biocontrol
Wow, woolly whitefly covered with waxy, curly filaments , Aleurothrixus floccosus.
One of the consequences of fire and the resulting ash is that the biocontrol agents that keep whiteflies, scale, mealybug and other pests in balance is that they will spend so much of their time preening that they don't have time to go after their prey. Lacewing larvae, minute pirate bug, ladybird larvae, parasitic wasps and others rely on moving around to get at their food sources. When they cant move fast, they stop and clean their joints to stay limber. Whitefly and scale insects just hunker down and don't need to do a lot of moving. They just breed, and without actively moving biocontrol agents, their populations can explode. Or that's my human analogy. In dusty areas or areas affected by ash, the particles get in their joints and they need to spend time cleaning in order to move fast.
Whiteflies suck phloem sap, which in some cases can cause leaves to wilt and drop when there are high numbers of whiteflies. However, the primary concern with whiteflies is the honeydew they produce. Honeydew excreted by nymphs and adults collects dust and supports the growth of sooty mold; large infestations blacken entire trees, including fruit, as well as attract ants, which interfere with the biological control of whiteflies and other pests. The sooty mold can also affect tree yields by reducing photosynthesis and requiring extra handling time for cleaning.
So pests under good control prior to a fire can get out of hand. This is a good example of a tree in the town of Ventura where ash was a problem. A seemingly clean tree, free of whitefly, started to defoliate with blotchy leaf spots. On the undersides of the leaves corresponding to the blotches are colonies of whitefly. And looking closely you can see that some of the nymphs have exit holes, indicating that they have been parasitized by a wasp. So nature is kicking in and taking it's course. The whitefly should get cleaned up soon too by some forager, such as lacewing larvae or pirate bug. No need to spray because it would just be a further disruption.
See more about whiteflies at:
Photos: Defoliating 'Meyer' lemon tree, blotches on upper side of leaf, whitefly colonies with exit holes in some of the nymphs
You always wanted to know what pollinated rambutan, litchi, blueberries and all those other plants dependent on insect pollen movement? O yes, and also what is pollinating avocado?
Insect Pollination Of Cultivated Crop Plants
by S.E. McGregor, USDA
Originally published 1976
The First and Only Virtual Beekeeping Book Updated Continuously.
Additions listed by crop and date.
This book is out-of-print, but can be found on-line at ABE Books and then you can get the images that are missing from the online version of the book
This is an old book with a lot of old information, but a lot of it is still good. There is definitely more up-to-date information, but this is a good starting point. For avocado, another good source, or course is AvocadoSource which also has quite a number of articles on pollination of other tree species
Recently a group of UC Riverside researchers met to align themselves around the topic of pollination - The biology, effects, interactions of the various pollinator and pollinizers and how they are affected by our environment and how we might be able to manage them better. The participants in this pollination group have all manner of expertise and hopefully their interaction will bring a synergy of understanding to this very complicated subject.
Photos: Syrphid (hover) fly, bumblebee, honeybee, thrips carrying pollen
The University of California Cooperative Extension conducted an Avocado Pest Management Round Table grower meeting in Fallbrook, CA on September 28, 2017. Approximately 64 growers, industry, Pest Control Advisors, and other stakeholders were present. Sonia Rios, Subtropical Horticulture Farm Advisor, University of California Cooperative Extension (UCCE), Riverside/San Diego Counties gave a talk on “Introduction to Avocado Weed Management.” Tim Spann from the California Avocado Commission (CAC) spoke on a potential threat to California's avocado industry, “A Review: Redbay Ambrosia Beetle & Laurel Wilt Disease.
Growers were able to participate in 2 round table discussions, one on “Old challenges/possible new solutions - pesticide resistance, proper spray application, new pesticides” and another on New Challenges in the Avocado industry. Round Table panel members were: Mary Lu Arpaia, University of California, Riverside/CE, Frank Byrne, University of California, Riverside/CE, Kevin Turner, CAL FIRE, Tim Spann, CAC, Enrico Ferro, Avocado Grower/PCA, Sonia Rios, UCCE, Victor Lopez, Crop Production Services.
The growers will be looking forward to the next Round Table meeting in the Spring. If you missed the meeting, below is a link to a recording of the meeting https://soundcloud.com/user-95194984/controlling-pests-in-avocado-roundtable-meeting
Argentine Ant is a very aggressive invader that disrupts native ant populations and at the same time disrupts biocontrol agents that help control, such pests as scale, aphids and mealy bugs in citrus and other tree crop species. They defend these sugar producing sources of energy from attack by predators and parasites, like parasitic wasps and predatory assassin bugs and lady bugs. They increase the threat of Asian Citrus Psyllid and HLB by protecting the psyllid from attack by parasitic Tamarixia.
A careful, well placed chlorpyrifos spray has been used to control Argentine ants. A trunk spray and/or spray on irrigation lines has disrupted their activity with minimal impact on beneficials. This protectant spray keeps the Argentine ants out of the canopies and allows the beneficials access to the pests. Controlling this one species, can have significant impact on biocontrol and the whole need for controlling pests.
Chlorpyrifos is a pesticide that might lose registration and other materials and techniques have been examined over the years as a replacement. A recent procedure has been proposed and used successfully on Santa Cruz Island to control introduced Argentine ants. The ant has caused tremendous disruption in biocontrol and it appears to have been controlled by this new technique. We are in the process of evaluating it's use in citrus. The application technique, costs and materials would need to be modified for use in citrus orchards. The current procedure would not be considered an organic practice since the pesticide material is not registered organic. It might be possible to use an organically registered material in the future.
Protocols for Argentine ant eradication in conservation areas
L.Boser1,C.Hanna2,D.A.Holway3,K.R.Faulkner4,I.Naughton3,K.Merrill5,J.M.Randall1,C.Cory1,D.-H. Choe6 & S. A.Morrison
Journal of Applied Entomology
The Argentine ant (Linepithema humile) is a widespread, abundant and ecologically disruptive invader that is present throughout major portions of coastal California and on half of the California Channel Islands. On Santa Cruz Island, the Argentine ant had invaded about 2% of the island's area in four distinct locations as of 2012. Given the negative ecological effects resulting from Argentine ant invasions,we sought to develop a cost-effective method of eradication. Here, we describe the results of large-scale, field-tested methods for Argentine ant eradication and post-treatment detection. Our eradication protocol employs a novel toxicant-delivery system: an aqueous solution of sucrose and 6 ppm of thiamethoxam mixed with hydrating polyacrylamide beads. Ants feed on the solution present on the bead's surface for about 24h after which time bead dehydration prevents feeding. We distributed hydrated beads by helicopter over 74 ha of infested areas plus a 50-m buffer on 14 occasions between June 2013 and September 2014. Treatments reduced Argentine ant activity to subdetectable levels within four months. In 2014, we conducted a high-intensity detection protocol using lures (n = 55 363) in areas treated in 2013.This effort did not detect Argentine ants. In 2015, we conducted a medium-intensity detection protocol using lures (n=2250) in areas treated in 2013 and 2014 but not searched in 2014; this sampling effort did not detect Argentine ant activity except for a single remnant infestation (c.0.3ha in area),which was retreated in2015.Thec ost of treatments was approximately $1400 per ha; this cost is comparable to other ant eradication efforts. The cost of our preferred detection method, which used lures spaced every 10m,was $500 per ha.These results demonstrate sufficient protocol efficacy to justify expansion of treatments to other infested areas in ecologically sensitive areas.
Photo: Argentine ant and scale
The Economist reports that Hungarian biologists have trained rabbits to preferentially eat common...