UC Agriculture and Natural Resources scientists based at UC Riverside are honing in on odors that might lure Asian citrus psyllids into traps, and other odors that will keep them away from citrus trees, reported Mark Muckenfuss in the Riverside Press-Enterprise.

Anandasankar Ray, professor in the Department of Entomology at UCR, along with two other researchers, published results recently that Ray believes are promising enough they may soon be adapted for grower use.

Ray and his team tested three attractant odors in El Monte backyards using yellow sticky traps. More than twice the number of psyllids were found in the scented traps compared to unscented traps, the article said. In time the researchers will also test chemicals that can mask odors that are pleasant to Asian citrus psyllids and some that repel the insects.

Other research projects underway at UC Riverside to combat Asian citrus psyllid and the disease it can spread were also noted in the Press-Enterprise article. They are: biological controls, including a tiny wasp imported from Pakistan that feeds on the psyllids; insecticides; developing resistant strains of citrus trees; finding a way to kill the bacteria spread by psyllids once it is in the tree; and discovering ways to identify diseased trees earlier.

It shouldn’t be news to local citrus growers and industry people that the Asian citrus psyllid (ACP) is being found with increasing frequency in the southern San Joaquin Valley. If this is news to you please follow the website at http://www.cdfa.ca.gov/plant/acp/ and/or sign up for U.C. entomologist Dr. Beth Grafton-Cardwell’s blog at;

http://ucanr.edu/blogs/ucanrorgblogscitruspest/.

Go to Beth’s website and in the upper right corner you can subscribe and receive the blog each time she sends one out. She also has a twitter account ‘ucanrbethgc’ that you can follow. This blog covers more than just ACP and is a great source of information on citrus IPM and citrus entomology. At the CDFA website, or through links to the site at Dr. Grafton-Cardwell’s blog, you can find maps delineating quarantine areas around new ACP finds, such as the one surrounding the recent find in the Wasco area (see attached map as an example). Regulations related to what needs to be done related to harvesting fruit and selling nursery trees growing within the quarantine zone can be found at:

http://www.cdfa.ca.gov/plant/pe/interiorexclusion/acp_quarantine_sjv.html

So far, there is no sign of HLB disease in the San Joaquin Valley, but that can change on short notice. Where ACP shows up, HLB disease (spread by a bacterium) is usually only a few years behind.

The weather is perfect for looking for Asian Citrus Psyllid.  There is new flush and that is where the adults go to lay their eggs and feed.  This is also the tissue where aphids and scale crawlers will be found, as well.

ACP has been active all this winter, but now is when they are going to be the most noticeable.  Get out there and look and alert the CDFA Exotic Pest Hotline to confirm a find, 1-800-491-1899.

ACP adult and nymphs with waxy exudate from nymphs.

For the last few years citrus growers in the San Joaquin Valley have been nervously watching the establishment of Asian citrus psyllid in southern California and bracing themselves for the day of northward movement.  That day arrived in November 2012 when two psyllids (Strathmore 16 Nov. and Terra Bella 21 Nov.) were caught on yellow sticky card traps, in addition to a third capture back in January 2012.  These captures have now resulted in restrictions on the movement of citrus in the heart of California's principal citrus production region.

Asian citrus psyllid is a small insect the size of an aphid that feeds on citrus leaves and stems.  It is the vector of a deadly bacterial disease of citrus called huanglongbing, often referred to as HLB or citrus greening.  This pest and disease combo has resulted in devastating losses to the citrus industry in Florida, and has the potential to have a similar affect in California.

Prior to November 2012 Asian citrus psyllid had been reported in eight California Counties, mostly in the southern part of the state, with a combined total of approximately 26,000 square miles under quarantine.  However, the two finds in Tulare County mark the first time the psyllid has been found in the heart of California's principal citrus production region of the lower San Joaquin Valley: Kern, Tulare and Fresno counties produce over 200,000 acres of citrus at an annual value of approximately $1.7 billion.

The capture of individual psyllids on sticky traps in Strathmore and Terra Bella gives CDFA the authority to establish a quarantine of citrus within a 20-mile radius of the find in Strathmore.  Prior to doing this, however, CDFA has opted as an interim step to only regulate citrus in a 5-mile radius around each find until further trapping and delineation can determine if psyllids are truly established in the region, or if the psyllids caught were just non-breeding hitchhikers brought to the corridor along State Highway 65 from infested counties in Southern California.  If further delineation detects an established population it is anticipated that quarantines would be established.  If established, a quarantine for Asian citrus psyllid would last a period of 2 years since the most recent capture.  If additional psyllids were captured during the two-year quarantine the clock would reset itself for another two years.

Due to the fact that the psyllid only feeds on leaves and stems (and not fruit), citrus growers within quarantine zones in California have several options for harvesting and shipping fruit.  Fruit harvested within quarantine zones can be picked, transported and packed within the quarantine zone without restrictions.  Once clean fruit is packed (no leaves or stems) it can be shipped to locations outside of the quarantine.

Packing fruit from within the quarantine at packing houses outside of the quarantine is also possible under a CDFA compliance agreement that can be accessed through the County Agricultural Commissioner.  These agreements state that the grower is willing to comply with CDFA and USDA regulations regarding the movement of bulk citrus, the most important of which is that bulk citrus must be processed through trash-removal equipment (to remove all leaves and stems) before it is shipped in bulk to a packer outside of the quarantine.

The Asian citrus psyllid quarantine also affects retail nursery stock.  Currently there are compliance agreements and protocols available that allow retail nursery stock to be moved within the quarantine zone.  However, no provisions are currently available to move nursery stock from the quarantine zone to regions outside of the quarantine zone unless the plants were budded and produced within a federally-approved screenhouse facility.

Regulations regarding Asian citrus psyllid can change quickly.  For that reason citrus growers are encouraged to maintain good contact with their local Agricultural Commissioner.  Additional information on the status of quarantines and other restrictions can be found online at

http://www.cdfa.ca.gov/plant/acp/.

Photo below.  Asian Citrus Psyllid nymphs with waxy exudates from feeding.