Archive for November, 2008

Photo Series: Lacewing Larvae Units

Published November 20, 2008 Life on the Farm , RVI Leave a Comment
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We’re starting a series of photo posts here at The Bug Farm. Every few weeks, we’ll be putting up some slices of life with quotes and helpful tips from the Rincon Vitova Team. The captions might be a bit formal, but we’re working on a system to have some slide shows which will make it all the better. Stay tuned!

Resident entomologist Ron Whitehurst inspects a Lacewing Larvae Unit for larvae size and distribution at Rincon Vitova Insectaries in Ventura, Calif., on Wednesday, October 17, 2008. “They start out as an egg about 1/30th of an inch and are 5/8th inch when full grown,” explains Whitehurst. Using syringe like pincers to inject digestive enzymes and liquefy their prey, the lacewing larvae “can become effective predators for any soft bodied insects.”

Kyra Ankenbruck and Ron Whitehurst drop moth eggs into the lacewing larvae units in the assembly room at Rincon Vitova Insectaries in Ventura, Calif., on Wednesday, October 17, 2008. The eggs act as a food source during transit. “They’ll have enough food while en route to end users plus they will eat any other lacewing larvae in the cell. [The customer gets] whoever wins.” Ankenbruck says with a smile. Lacewing larvae are voracious predators resorting to cannibalism if there is no other prey.

Jan Dietrick demonstrates how to check the larvae by tapping the unit above white paper. Each unit is filled 115% to ensure each of the 500 cells will have a larva. “Our standard is to overfill the units,” Dietrick explains. “You have to tap the back really hard, because the little larvae may hold onto the inside of the cells.” This same method is used for in-field release of the larvae on infested foliage.

Stacks of Lacewing Larvae Units stand behind the glue board in the assembly room at Rincon Vitova Insectaries in Ventura, Calif., on Wednesday, October 17, 2008. The glue glob on the board has grown layer by layer as a paint roller is used to glue the organdy covers on. Kyra Ankenbruck encountered the glue board in May 2006. “It wasn’t much smaller than now,” Ankenbruck comments.

Kyra Ankenbruck waters down the floor of the Lacewing Larvae Unit incubation room at Rincon Vitova Insectaries in Ventura, Calif., on Friday, November 14, 2008. In dry weather, watering the floor keeps the high humidity the larvae need. “You wouldn’t believe how many we’ve lost when the Santa Anas [hot California winds], blow in,” says Ankenbruck.

For more info on Lacewings and their larvae, check out Rincon Vitova’s Lacewing Bulliten.

All Images copyright: Bryce Yukio Adolphson © 2008 and may not be reused without express permission.

Getting microbes on your team: Soil food web basics

Published November 19, 2008 Ecology Leave a Comment
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When I started at Rincon-Vitova in July, I saw a book in the break room called Teaming with Microbes: A Gardener’s Guide to the Soil Food Web. I’ve been gardening whenever I have the space since I was eight and plants are so interesting to me that I got a biology degree focused on them, but I’d never heard of a soil food web before. I know mostly about the macroscopic parts of a garden ecosystem: dirt, water, plants, and bugs. Of soil microbiology, all that was usually mentioned in my botany classes was the nitrogen-fixing Rhizobium bacteria and mycorrhizae, the fungi that help plant roots reach farther and absorb more. Books and websites I read to further my hobby talked about the negatives of soil biology – nematodes, wilts, damping off. This looked like an interesting change of pace. So I picked up the book and started reading.

The part of the soil food web that you can see – the bugs and earthworms around a plant’s roots – rely on an entire microscopic world of bacteria, fungi, nematodes, and protozoa. You’ve probably heard about the qualities of good soil: dark, moist, full of organic matter and earthworms. Besides being able to hold water well, this soil supports life. Land that’s been used for intensive farming and land that has recently been developed is missing this key living component. This is part of the reason why home gardeners are seen fertilizing their lawns and battling fungal diseases regularly. Dirt with no life in it doesn’t support life very well.

The microbes in soil can help plants in a few different ways. I mentioned mycorrhizae earlier. They are fungi that evolved a handy symbiosis with plant roots. The roots secrete simple sugars at the root hairs. In exchange for this food, the mycorrhizal fungi pass water and nutrients to the plant. Of course, plants can absorb nutrients and water without the fungi, but the fungi increase the amount and range of stuff the roots can absorb. Besides mycorrhizae, there are microbes that help break down decaying material and unlock the nutrients, microbes that bind soil together into water-holding clumps, microbes that release chemicals that stimulate plant growth, and microbes that protect the plants from other microbes. The last category is one that many gardeners probably notice without realizing it. Without the defense of beneficial microbes, plants are vulnerable to root-knot nematodes and a whole slew of fungal diseases. There are a few ways gardeners can help out these microscopic workers. Incorporating compost, manure, or other organic matter into the soil can give the microorganisms already there a moist and comfy home, as well as a food source. If a lot of the microbes have been killed off, they can be replenished with a well brewed compost tea. Commercial inoculants of specific species are also available. There are many facets of a health soil food web. As I learn more about the soil food web, I’ll share it with you.

Organic Methods Could Help Rescue Honeybees

Published November 18, 2008 Ecology Leave a Comment
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Effects of pesticides on Apis mellifera, the European honeybee, is at the top of the agenda of the new California Apiary Board appointed by the Secretary of Food and Agriculture. With the spread of Colony Collapse Disorder (CCD), this is an extremely urgent matter to investigate. The nutritional health of the bees is also an obvious factor that might relate to CCD. This season being so dry (witness the extensive wildfires), there isn’t as much forage for the bees. Fewer summer wildflowers (and less pollen) decrease winter food reserves, which may contribute to bee die off. Corn and soybean pollen offer little nutrition for bees.

However, arthropod pests also decimate bees, probably more so when they are weakened by pesticide exposure and poor nutrition. Bee pests include varroa mites, tracheal/external mites, small hive beetles, wax moths, ants, and also other bees, wasps, bee lice, dragonflies, spiders, predatory bugs, cockroaches, earwigs and termites. As a hobby-beekeeper with an avid interest in biological pest control, I would like to recommend that the new Board look closer at the non-toxic biological controls that may protect bees from insect and mite pests. Here are some examples:

Varroa mites have been reduced with insect eating fungi (entomopathogenic). Tests by USDA with a particular strain of Metarhizium anisopliae, showed good reduction of the varroa mite with no apparent harm to the bees. Follow up studies were done with another strain that was not effective. The price for treating a hive looks like $1-$2 per hive which seems competitive for organic. Currently there is no commercial supply in US. There are producers in India that can ship to US. Production is simple on cooked rice. This fungus is used in huge quantities in North Africa to control the desert locust, and is called green muscle after the green fuzzy spores sprouting from the dead insects.

Conidiobolus coronatus is a gossamer, phantom fungus, quite unlike anything you have ever seen before. It eats a lot of soft-bodied insects but not bees (hymenoptera). It seems to be good at reducing varroa mite, hive beetle, wax moth and termite. This product is only developmental, not sold as a control. However, it is sold as an inoculant for the hive. Powdered sugar helps. A screened bottom board with a sticky plastic sheet traps mites for monitoring.

Tracheal Mite can be controlled with menthol or a combination of thymol, eucalyptus and menthol. Some trials with smoke from eucalyptus or citrus leaves showed promise for this strategy. Grease patties and powdered sugar work well. Some predator mite may be found that would live in the hive and feed on the pest mites – Hypoaspis was tried without good results.

The small hive beetle Athina tumida, North America’s newest bee keeping pest, was first discovered in Florida in the spring of 1998. The above fungi are possibilities for the larvae in the hive. The larvae drop to the soil to pupate where you can treat with insect eating nematodes, such as Heterorhabditis bacteriophora (Hb). This nematode is commonly used to control white grubs in lawns. A suspension of the nematodes is sprayed on the ground around the hive and watered in.

Wax moth larvae eat the comb in weak hives or stored frames. Trichogramma, a minute parasitic wasp lays its eggs in moth eggs and the wasp larva eats the moth egg. Bt (Bacillus thuringiensis), a bacteria that makes caterpillars sick, can be sprayed on comb before it is stored, though it is not currently registered for this use. Light traps can reduce the adult moths in storerooms.

Ants can be excluded (along with roaches, earwigs and termites) with water or oil traps on the legs of the hives. A bait of boric acid, sugar and water, placed in plastic bait stations around the hive, will be taken back to the colony where it will knock down the colony. AntPro is the best of the bait dispensers.

Roaches and earwigs are attracted to yeasty baits like beer into mechanical traps. Slug Saloon with powdered beer bait traps earwigs and sow bugs as well as slugs. To make a roach trap, coat the inside neck of a pint jar with petroleum jelly and bait with a small piece of white bread moistened with beer.

I would like to see organic protocols for beekeeping be a top priority, which is a big challenge with invading pests. Of course a well-designed hive, good forage, and supplemental feeding gives the bees a chance to take care of themselves. When pests and diseases show up, beekeepers need access to knowledge about natural, integrated treatments that don’t stress the bees. The appointment of the new bee board shows the importance for California agricultural of honeybees for pollinating, especially almonds. Do you have other angles on bee problems, tips, suggestions, or questions? I look forward to hearing from everyone interested in organic beekeeping.

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