Susan Halbert, an entomologist for the Florida Department of Agriculture and Consumer Services, Division of Plant Industry, was the first to record U.S....[More]
THE DISCOVERER:
Susan Halbert, an entomologist for the Florida Department of Agriculture and Consumer Services, Division of Plant Industry, was the first to record U.S. sightings of both the Asian citrus psyllid, in 1998, and huanglongbing in 2005. She’s standing in the Florida State Collection of Arthropods, a museum with more than 9 million insect specimens, which she uses for reference when identifying pests.
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Anna Kuchment
THE VECTOR:
A drawer of dried and mounted Asian citrus psyllids from the Florida State Collection of Arthropods.
An adult Asian citrus psyllid. The U.S. has many native psyllids, which are common sap-sucking insects that do not cause major plant damage. Asian citrus psyllids ( Diaphorina citri ) likely originated in South Asia and have become the major spreaders of huanglongbing around the world....[More]
THE VECTOR UP CLOSE:
An adult Asian citrus psyllid. The U.S. has many native psyllids, which are common sap-sucking insects that do not cause major plant damage. Asian citrus psyllids (Diaphorina citri) likely originated in South Asia and have become the major spreaders of huanglongbing around the world.
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Mike Lewis, Center for Invasive Species Research, University of California Riverside
THE VECTOR AT WORK:
An Asian Citrus Psyllids feeding on a citrus tree. The pests sit with their behinds raised at a characteristic 45-degree angle.
[Link to this slide] Mike Lewis, Center for Invasive Species Research, University of California Riverside
DISEASE MANAGERS:
From left to right: Tim Willis, manager of the McKinnon Corporation, an orange grower in Winter Garden, Florida; Philip A. Stansly, professor of entomology at the University of Florida’s Institute of Food and Agricultural Sciences in Immokalee; and Maury Boyd, president of the McKinnon Corporation....[More]
DISEASE MANAGERS:
From left to right: Tim Willis, manager of the McKinnon Corporation, an orange grower in Winter Garden, Florida; Philip A. Stansly, professor of entomology at the University of Florida’s Institute of Food and Agricultural Sciences in Immokalee; and Maury Boyd, president of the McKinnon Corporation. Stansly has researched the best ways to manage huanglongbing using pesticides, fertilizer and other nutritional supplements, and many other approaches. Nearly all of McKinnon’s trees are infected with HLB, but Boyd and Willis say their enhanced nutrition program has helped the trees survive.
Boyd’s decision to not uproot his infected trees has come under criticism. Research shows that uprooting sick trees, in combination with pesticide sprays and other measures, is key to keeping infection rates low. Some scientists say his trees serve as “Typhoid Marys,” providing a reservoir for psyllids that could then spread HLB to neighboring commercial groves.
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Anna Kuchment
THE DAMAGE:
A leaf shows the characteristic signs of huanglongbing: yellowing and asymmetrical mottling. Symmetrical mottling is usually a sign of nutritional deficiency, such as a lack of zinc.
Freshly picked Valencia oranges waiting be hauled away and squeezed into juice. Boyd, president of McKinnon Corporation, says the disease has not diminished his yield but has raised his costs by 40 percent because of the need for more insecticide sprays and fertilizers.
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OFF TO MARKET:
Freshly picked Valencia oranges waiting be hauled away and squeezed into juice. Boyd, president of McKinnon Corporation, says the disease has not diminished his yield but has raised his costs by 40 percent because of the need for more insecticide sprays and fertilizers.
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Anna Kuchment
UNDER LOCK AND KEY:
Young nursery trees grow inside psyllid-proof screen houses at the University of California, Riverside. Because young trees are especially susceptible to huanglongbing, many of the ones destined for commercial orchards in the U.S....[More]
UNDER LOCK AND KEY:
Young nursery trees grow inside psyllid-proof screen houses at the University of California, Riverside. Because young trees are especially susceptible to huanglongbing, many of the ones destined for commercial orchards in the U.S. are now raised inside these screened-in structures.
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Anna Kuchment
BRING IN THE WASPS:
As an invasive species, Asian citrus psyllids have few effective predators in the U.S. so scientists traveled back to the psyllids’ homeland to find their natural enemies....[More]
BRING IN THE WASPS:
As an invasive species, Asian citrus psyllids have few effective predators in the U.S. so scientists traveled back to the psyllids’ homeland to find their natural enemies. Mark Hoddle, an entomologist at the University of California, Riverside, has imported tiny wasps known as Tamarixia radiata (pictured) from Pakistan to parasitize Asian citrus psyllids in California. He has been releasing them in residential areas of Los Angeles, where the state has stopped spraying pesticides.
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Jason Mottern, Department of Entomology, University of California Riverside
FEEDING FRENZY:
Psyllid nymphs produce waxy honeydew as they feed on trees.
[Link to this slide] Mike Lewis, Center for Invasive Species Research, University of California Riverside
PATH OF DESTRUCTION:
Tamarixia radiata wasps kill psyllids by laying eggs on the bellies of young psyllid nymphs. Once the wasp hatches, it eats the nymph from the outside in and then bursts out, leaving a nymph “husk” with a hole in it.
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PATH OF DESTRUCTION:
Tamarixia radiata wasps kill psyllids by laying eggs on the bellies of young psyllid nymphs. Once the wasp hatches, it eats the nymph from the outside in and then bursts out, leaving a nymph “husk” with a hole in it.
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Mike Lewis, Center for Invasive Species Research, University of California Riverside
YES! Send me a free issue of Scientific American with no obligation to continue the subscription. If I like it, I will be billed for the one-year subscription.
The wasp species in question is Tamarixia radiata.
There's an excellent detailed article on these wasps at http://entnemdept.ufl.edu/creatures/beneficial/wasps/tamarixia_radiata.htm with much more information than is supplied here.
What I haven't seen is any sign that anyone has studied the potential downside of introducing the wasps. We know what the psyllids are up to; what will the wasps decide to do?
rugeirn: the feature lays out more information about the wasps, this is only supplementary material. But they have an extremely narrow host range, and the Hoddles have pitted them against native flora and fauna in California and have found that they attack only Asian citrus psyllids. Here's a link for some more info from UC Riverside: http://newsroom.ucr.edu/2819
as a horticulturist, i feed my citrus with the following- at 5#/100 sq ft, or two handfuls/plant around feeding zone- NOT ON CROWN! blood meal, cottonseed, low n formulation bat guano(sub bird guano, or soft rock phosphate), green sand, dolomite, rockdust, humate, prilled sulfur, then just a spoon of both kelp meal and actinoiron for each plant (imagine that rate(for kelp and iron) at 1#/100 sq ft). cover with 1 or 2 inches of steer manure, NOT BARK OR SAWDUST PRODUCTS (DUE TO S.O.D.). YOU SHOULD SEE IMMEDIATE IMPROVEMENT IN A FEW WEEKS. I DO THIS AFTER THE LAST FROST DATE EVERY YEAR. during the growing period, i use all season oil on the trees to control insect damage, averaging a spray every two weeks at least, set on 1 T/gal setting. this step would help to control this disease, but keeping your plants healthy is the better step. if just planting make sure you use two inches of lava sand, or 1/4" grade lava chips, with one inch of oly#2 sand to increase drainage under citrus- the #1 problem i see in the bay area in gardening. dig in 2-4" cow manure, and use manure for your topping. note on nitrogen use- if your tree is yellow, use blood meal, if it is light then use cottonseed. in late summer you may need to readdress plant need due to intense heat- keep it light, and balanced. avoid any inorganic salt fertilizers- citrus hate them, the soil structure is destroyed, and you can taste it, yech! if your plants are in container, just a spoon of each, then manure. citrus do not want to dry out, but do not overwater. an inch per week should do. good luck.
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4 Comments
Add CommentThe wasp species in question is Tamarixia radiata.
Reply | Report Abuse | Link to thisThere's an excellent detailed article on these wasps at http://entnemdept.ufl.edu/creatures/beneficial/wasps/tamarixia_radiata.htm with much more information than is supplied here.
What I haven't seen is any sign that anyone has studied the potential downside of introducing the wasps. We know what the psyllids are up to; what will the wasps decide to do?
rugeirn: the feature lays out more information about the wasps, this is only supplementary material. But they have an extremely narrow host range, and the Hoddles have pitted them against native flora and fauna in California and have found that they attack only Asian citrus psyllids. Here's a link for some more info from UC Riverside: http://newsroom.ucr.edu/2819
Reply | Report Abuse | Link to thisSo, farewell to the orange juice industry. That will blow up the same down the border, actually, Veracruz, as far as I know.
Reply | Report Abuse | Link to thisas a horticulturist, i feed my citrus with the following-
Reply | Report Abuse | Link to thisat 5#/100 sq ft, or two handfuls/plant around feeding zone- NOT ON CROWN!
blood meal, cottonseed, low n formulation bat guano(sub bird guano, or soft rock phosphate), green sand, dolomite, rockdust, humate, prilled sulfur, then just a spoon of both kelp meal and actinoiron for each plant (imagine that rate(for kelp and iron) at 1#/100 sq ft).
cover with 1 or 2 inches of steer manure, NOT BARK OR SAWDUST PRODUCTS (DUE TO S.O.D.). YOU SHOULD SEE IMMEDIATE IMPROVEMENT IN A FEW WEEKS.
I DO THIS AFTER THE LAST FROST DATE EVERY YEAR.
during the growing period, i use all season oil on the trees to control insect damage, averaging a spray every two weeks at least, set on 1 T/gal setting.
this step would help to control this disease, but keeping your plants healthy is the better step.
if just planting make sure you use two inches of lava sand, or 1/4" grade lava chips, with one inch of oly#2 sand to increase drainage under citrus- the #1 problem i see in the bay area in gardening. dig in 2-4" cow manure, and use manure for your topping.
note on nitrogen use- if your tree is yellow, use blood meal, if it is light then use cottonseed. in late summer you may need to readdress plant need due to intense heat- keep it light, and balanced.
avoid any inorganic salt fertilizers- citrus hate them, the soil structure is destroyed, and you can taste it, yech!
if your plants are in container, just a spoon of each, then manure. citrus do not want to dry out, but do not overwater. an inch per week should do.
good luck.