Christina Hoddle

Observations of Red Palm Weevil Management in France

Anonymous — Mon, 20 Jan 2020 02:22:49 +0000

Observations of Red Palm Weevil Management in France Anonymous (not verified) Sun, 01/19/2020 - 18:22 More Blog Posts Christina Hoddle December 16, 2010

On a recent trip to southern France, I discovered firsthand how destructive red palm weevil (RPW) could be for California if we don’t act fast to eradicate and control this pest.

Unfortunately, for a variety of reasons, the French didn’t have the ability to stop this pest before it exploded into the massive problem they currently face. To comprehend the gravity of their situation, today, the area in France that had the initial outbreak of this pest (La Croix Valmer) has an estimated loss of 80% of their Phoenix palm species; but it doesn’t stop there. This insect has since spread to 5 departments within France with a total estimated loss of 1 million euros per year (~$1.4 million US) with no end in sight. The departments affected by this insect include some famous top-end tourist destinations like St Tropez, Cannes, Monaco, Nice, and Marseille where palm trees are used as symbolic imagery for these areas (think of the Cannes Film Festival-Palm D’or). I believe most of the areas in France with large scale palm production or plantings have been affected by two serious palm pests, the RPW and a day flying moth, Paysandisia (affecting at least 8 departments in France). Hopefully we can learn from the French experience to keep California from realizing the same catastrophic fate.

Map of French Departments with known infestations of Rhynchophorus ferrugineus (RPW) (Colored Red) and Paysandisia archon (Colored Yellow). Most areas with RPW also have Paysandisia.

RPW, or Charançon Rouge du Palmier in French, was first detected in France in La Croix Valmer (near St Tropez) around 2004. This was the first detection of RPW by palm growers, but the enormity of the find was not realized, and it was dismissed as a non-event by the French Plant Protection Services. Consequently, RPW wasn’t officially reported as established in France until 2006, 2 years after the initial find. Then, through a European directive, RPW was deemed a quarantine pest in May 2007 and the only approved treatment for RPW infested palms in France was complete tree removal and disposal. During this time, the French were already overwhelmed by another palm pest; Paysandisia archon, a day flying moth from South America whose larvae tunnel into palm fronds and trunks. The damage caused by RPW and Paysandisia are difficult to tell apart because the larvae of both species cause very similar feeding damage and palm mortality. From my brief experience in France, it appeared that the areas where Paysandisia were initially detected have been taken over by the even more ravenous RPW. We should be looking out for Paysandisia in California as well because it will be extremely destructive should it invade and successfully establish. Additionally, perhaps Paysandisia will make it even easier for subsequent RPW populations to flourish by weakening palms and making them more vulnerable to RPW attack.

In Le Var (Department 83 on map), a group of concerned citizens made up of local growers, nursery owners, researchers (INRA/Phoenix Research Station), and city workers decided to band together to form a non-profit organization to give some weight to their fight against RPW and to obtain support from the French government agencies for managing this pest. This non-profit group, FDGDON (Fédération Départementale des Groupments de Défense contre les Organismes Nuisible) du Var, formed in June of 2007 with 135 members and continues to fight the RPW problem today. However, FDGDON du Var has minimal support from the French Government which has been very slow in responding to the obvious need to develop RPW management programs.

I had the opportunity to spend a day with this dynamic group in Hyères, France to see up close the daily challenges they face with RPW. Hyères is a typical, small picturesque French seaside town about 10 miles east of Toulon. Palms trees of all varieties are quite abundant in the landscape. You really can’t go more than a block without seeing one…or now for that matter, one that has had to be removed leaving an ugly stump in the ground.

Local park in Hyères France that has been affected by RPW.

All of these concerned individuals have other full time jobs but spend a lot of time dedicated to FDGDON du Var because the RPW invasion has affected their livelihoods and degraded the aesthetic appeal of local neighborhoods, so collectively they want something done about managing this pest. RPW has been problematic in the area where FDGDON du Var has been active for the past ~4 years yet the group is still struggling with the French Government to enact basic protocols and procedures to help them solve the RPW problem. I attended their annual board meeting (17 November 2010 in Hyères) and was amazed at how much red tape FDGDON du Var has to push through when dealing with RPW management which is overseen by federal and local government agencies. It was very obvious from the extremely heated discussions the high levels of frustration with this bureaucracy while RPW slowly eats away at the palms in their backyards and along their road sides. One of the biggest surprises for me was that they are still trying after ~4 years to get their training program, to train individuals to detect and treat for RPW and to remove and dispose of infested palm trees, officially recognized by the French government (~150 individuals have been trained, but the certificates are not valid, thus essentially not recognized as trained for all practical purposes). Without established and effective management protocols in place, many people take it upon themselves to do what they think is best to manage RPW and dispose of dead and infested palms. For example, some people do nothing, which exacerbates the RPW problem for others. Unscrupulous folks claim to know what they are doing and improperly remove palms and dump them into landfills untreated and unchipped, leaving live RPW in exposed palm carcasses ready to emerge and exploit new areas. These fly-by-night palm removers charge less for these budget services which undercuts the responsible landscaping companies who are doing the right thing by chipping and disposing of RPW-infested palms properly.

The French seem to still be struggling to keep up with the RPW invasion in the absence of official recognized training protocols and with a general resistance to review the pesticide list, application rates and methodologies more efficiently. In comparison, other countries in Europe (e.g., Spain and Italy) have had established RPW protocols and preventative treatments in place for awhile (which were also implemented in already advanced stages of pest numbers so consequently they are still struggling with control) while France is still bogged down in prolonged administrative processes; issues that after ~4 years were only recently partially addressed in July 2010 due to the insistance of FDGDON. The French should have learned from the other European countries examples but it doesn’t appear to be the case. It will be tragic if these coastal French towns lose this battle with RPW when something can be done if the right resources are made available. FDGDON du Var is pushing forward with its battle against RPW and Government bureaucracy, albeit slowly.

The lesson from France for California RPW managers is obvious; fast and decisive actions against RPW are needed. California doesn’t have to face the same fate as Hyères and other French coastal towns. It may seem expensive to remove and destroy infested palms or to bring in RPW experts from overseas to help implement major control and research programs; but the alternative of “wait and see” will be exponentially worse and vastly more expensive. Can you imagine California’s urban, and desert oases without palm trees?? How about the date plantations in the Coachella Valley? Date shakes anyone?

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Christina Hoddle

France

Red Palm Weevil

Red Palm Weevil Outreach Meeting in Coachella Valley

Anonymous — Mon, 20 Jan 2020 02:21:46 +0000

Red Palm Weevil Outreach Meeting in Coachella Valley Anonymous (not verified) Sun, 01/19/2020 - 18:21 More Blog Posts Christina Hoddle January 14, 2011

Albert Keck of Hadley Farms discussing Date Palm Production with RPW meeting attendees

While the Red Palm Weevil (RPW) infestation seems to be in a quiescent phase in Southern California, the community of researchers, public officials, arborists, nursery owners, and palm growers are getting ready for the imminent counter attack. This problem is being addressed aggressively and a series of RPW Outreach meetings sponsored by California Department of Food and Agriculture are being scheduled across Southern California over the next month. The purpose of these meetings is education and outreach to those individuals and groups that are on the frontline dealing with this ravenous pest. The more aware individuals are, especially those who may come across these insects in their daily lives (during work in the landscape, or gardening around the home), the better chance of detecting and containing the spread of this pest.

The first meeting in this RPW outreach series was held at the Coachella Valley Water District Forbes Auditorium on January 6, 2011. This well attended gathering was led by John Snyder, the Riverside County Agricultural Commissioner and supported by CDFA and USDA officials. The dynamic schedule included a talk by Nick Nisson (Orange County Ag Commission Entomologist) who discussed the basic biology of RPW, detection methods, and presented preserved RPW specimens (adults, larvae, and cocoons) for inspection by audience members. The meeting continued with a talk by Laura Petro (CDFA, Senior Agricultural Biologist) who discussed the current trapping and surveillance activities around find sites in Laguna Beach. Nawal Sharma (CDFA Pest Exclusion Branch) furthered the discussion with the potential regulatory impacts this pest will have on local industries. John Kabashima (University of CA Extension County Environmental Director) detailed how everyone could do their part in detecting, monitoring and reporting this pest. The meeting was concluded by David Pegos (CDFA, Special Assistant) discussing other outreach opportunities followed by a question and answer period.

Hadley Farm worker getting ready to dethorn Date Palm Tree

Posters and flyers, in English and Spanish, describing this insect and how to detect and report it were distributed. There was talk about having this meeting in Spanish and/or a Spanish video presentation made so that native Spanish speakers who work directly in or with palm trees have a better understanding of this problem and will be well aware of this pest and in a position to report finds.

Once the meeting concluded, Albert Keck, from Hadley Farms, generously gave an informational tour to local officials and researchers who attended the meeting of local date palm plantations including the demonstration by one of his highly skilled workers on how to dethorn a palm tree- an amazing site to see! This added bonus gave us an appreciation for how much work is involved in maintaining a date palm plantation and how devastating RPW could be to so many people’s livelihoods in the Coachella Valley.

Overall the meeting was a success for everyone involved. Information dissemination in this manner is potentially very powerful, and with additional meetings scheduled it is anticipated that the momentum from these outreach efforts can help control the RPW invasion in Southern California.

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Christina Hoddle

News

Red Palm Weevil

Testing Red Palm Weevil Pheromone Traps in the Philippines

Anonymous — Mon, 20 Jan 2020 02:04:41 +0000

Testing Red Palm Weevil Pheromone Traps in the Philippines Anonymous (not verified) Sun, 01/19/2020 - 18:04 More Blog Posts CISR Team November 07, 2011

In August 2010, red palm weevil (RPW), was officially detected in Laguna Beach, Orange County California. This insect was recovered from a dying Canary Islands palm in a residential property and has been declared by FAO to be the world’s most destructive palm pest. At least 2-3 additional palms are thought to have been killed by this insect in Laguna Beach, and two Canary Islands palm trees showing RPW damage have been treated with insecticides. Intensive trapping efforts by CDFA for more than one year using the commercially-available RPW aggregation pheromone, ethyl acetate (weevil magnet), and fruit additives placed together in bucket traps have failed to capture RPW in the immediate vicinity of previous detection sites.

LEFT: The orange form of R. ferrugineus RIGHT: The black with red stripe form of R. ferrugineus

This pheromone-based trapping program has been used successfully for monitoring in other countries where the orange and black form of R. ferrugineus has invaded, and it is an important management component of IPM programs in Middle Eastern commercial date plantations for this pest.

A major point of interest regarding the trapping program in California using the commercially available RPW pheromone is whether or not it is attractive to the red palm weevil morph found in Laguna Beach. The RPW color morph found in Laguna Beach is black with a prominent dorsal red stripe that runs from the rear margin of the head across the thorax to the anterior margin of the abdomen. Until its detection in southern California this red stripe form of RPW was only known from southeast Asia (e.g., south Thailand, Malaysia, Indonesia, and the Philippines.)

To assess the attractiveness of the commercial RPW pheromone used by CDFA in Laguna Beach to the “vulneratus” morph, a small trial was run in a 60 ha commercial coconut plantation in Quezon on Luzon Island in the Philippines from 20 October 2011 to 26 October 2011. This area has been reported previously to have both RPW color morphs in sympatry. Three treatments were set up and checked twice per day at 6:00am and 4:00pm for captures of RPW:

Treatment one:This treatment consisted of traps with RPW aggregation pheromone + ethyl acetate (weevil magnet) + fermented dates. The aggregation pheromone and weevil magnet were supplied by CDFA and are the same products being used to monitor for RPW in Laguna Beach. Previous studies have demonstrated that fermented dates are an extremely potent “additive” to this set-up for attracting the orange and black morph of RPW. Dates were used for 3 days and then replaced with cut pieces of palm hearts. Traps were hung either in immature coconuts (a highly preferred host stage for RPW to attack) (see photo below) or on dead coconut trunks ~ 2.0 m above the ground (a height similar to that of CDFA deployed traps in Laguna Beach). This treatment was replicated three times in the plantation.

Treatment 2: Freshly felled coconut palms that were bucked, stacked, and had palm hearts arranged on the wood pile were inspected for RPW attracted to this resource. This treatment was replicated three times. The plantation owner was asked to fell five palms that were suspected to be infested with RPW. All five palms exhibited extensive internal damage, but no RPW life stages were found and it is was difficult to determine if feeding damage had been caused by RPW or another serious coconut pest, Oryctes rhinoceros beetles.

Treatment 3: This treatment consisted of Treatment one (bottle trap with RPW pheromone + ethyl acetate + fermented dates or palm hearts) and Treatment two combined and was replicated three times at different sites in the plantation.

Results: The results of these trials were clear cut and consistent. Treatments one and two did not result in the capture of any RPW over the 6 day monitoring period. Treatment three, pheromone bottle traps placed on freshly cut stumps of coconut palms with cut sections of palm trunk and palm hearts resulted in the capture of 23 RPW over the course of the trial. All three replicates of Treatment three resulted in the capture of RPW and the first captures were made ~ 24 hr after the palms were felled, sectioned, and stacked with the pheromone bottle trap. Captures ranged from 1 – 5 RPW at a site. RPW were found either inside the bottle traps, or more often underneath the wood stacked on top of the palm stump, or in chainsaw blade width slices made into bucked pieces of palm trunk. Adults are exceptionally thigmotactic and can push themselves deeply into very tight crevices, hence the notches on the cut pieces of palm trunk.

The color morphs of RPW that were captured in Treatment three included R. ferrugineus, “R. vulneratus”, and a color and pattern spectrum between these two distinct forms.

In the photo above, the global invading RPW morph (orange and black) is seen on the extreme left (two specimens), the “vulneratus” morph that has invaded Laguna Beach is third from the left, and the remaining “vulneratus” variants exhibit various red and black markings and at the extreme end (last two specimens on the right), these dorsal markings have been lost entirely. All of these weevils were captured in one night across all three replicates of Treatment three.

A Red Palm Weevil inside a bottle trap in Treatment 3 is covered in phoretic mites

The sex ratio of captured RPW was highly female biased (n = 18 females [78%]; n = 5 males [22%]). Unidentified phoretic mites were found on 60% and 67% of males and females, respectively. Phoretic mites have been recorded previously on RPW adults but their potential role as control agents of RPW is uncertain.

The majority, 78% (n = 18) of RPW were captured when treatments were examined at 6:00am, the remaining 22% (n = 5) were captured at 5:00pm. This result suggests the RPW flight activity in the Philippines may be crepuscular or nocturnal.

Conclusions: The RPW traps baited with pheromone and weevil magnet (ethyl acetate) used by CDFA in Laguna Beach failed to capture any weevils in a commercial coconut plantation in the Philippines unless they were deployed in conjunction with freshly felled coconut palms. The pheromone + weevil magnet + fruit additives alone did not catch any weevils, nor did the fresh-cut palm logs attract any weevils. The reasons for this are not clear. This small study had low treatment replication and treatments were not blocked to account for site effects – although they were dispersed widely through the plantation. The bottle traps may not have been adequate for retaining RPW attracted to Treatment 1. This trial was run at the end of the monsoon season, a time of year reported to have low RPW activity. This situation may have been worsened by a wetter than normal “dry” season (the owner of the coconut plantation indicated that the dry season had been unusually wet this year) that preceded the monsoon season and RPW densities may have been lower than normal for this time period.

Thus, our results suggest that the bait combinations being used in Laguna Beach may not attractive to the RPW morph that is present. Our results suggest that at a minimum, pheromone and weevil magnet baits should be deployed in combination with fresh-cut palm material, especially newly cut palm trunks and if possible this treatment should be set up and trialed in Laguna Beach to see if it can attract and retain RPW.

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Christina Hoddle

Mark Hoddle

Red Palm Weevil

Hunting for Natural Enemies of Asian Citrus Psyllid in Pakistan

Anonymous — Mon, 20 Jan 2020 02:03:46 +0000

Hunting for Natural Enemies of Asian Citrus Psyllid in Pakistan Anonymous (not verified) Sun, 01/19/2020 - 18:03 More Blog Posts CISR Team November 08, 2011

Asian citrus psyllid (ACP) was found in California in late 2008 in San Diego and Imperial Counties. This invasive pest sucks sap from citrus and is a major concern for California because when feeds ACP inject into trees bacteria that cause a lethal disease of citrus known as huanglongbing (HLB). This plant disease is incurable, is restricted to citrus, and poses zero (i.e., no) risk to humans. HLB is also known as yellow shoot disease or citrus greening.

This ACP-HLB combination has been particularly devastating following its arrival in major citrus producing areas. In Florida for example, 60,000 acres of citrus, about 10% of commercial production, was taken out by HLB within 4-5 years of the first detection of the disease. At the time this blog was written (November 2011), HLB had not been detected in California. However, many suspect that the disease is present in California, and could be residing undetected in backyard citrus, possibly in plants that were smuggled into the state from areas where HLB is present (e.g., Asia, Mexico, or Florida).

Since 2008, large ACP populations have developed in Los Angeles (LA), Riverside, and San Bernardino, Counties. The vast majority of infestations found by the California Department of Food and Agriculture’s (CDFA) monitoring program have been detected in urban areas. Citrus is a very popular backyard fruit tree and homeowners grow a large variety of different citrus including oranges, mandarins, lemons, limes, kumquats, and grapefruit. It has been estimated that there is more citrus growing in people’s gardens than there is in all of California’s commercial citrus production areas combined. Surveys by UC Riverside scientists working on ACP in LA have found that ACP is encountered most often on lemons and limes, and populations can reach very high levels on Mexican limes, which appear to be a highly favored host.

Containing ACP in urban areas is a major challenge that the CDFA and Citrus Research Board (CRB) have jointly undertaken. The management plan involves treatments of residential trees that have ACP and neighboring trees within a prescribed distance of the infested tree that triggered treatments. Pesticide applications may include foliar sprays to kill ACP eggs, nymphs, and adults, and soil drenches with approved systemic insecticides that move inside the plant killing ACP when they suck sap. Finding and treating ACP infested citrus is a difficult and expensive task, and some homeowners don’t like the idea of pesticides being applied to citrus in their gardens.

UC Riverside with support from CDFA, CRB, and the Citrus Health Response Program (CHRP) has initiated a classical biological control program for ACP. This approach to ACP control involves finding natural enemies of the pest in its native range. Most scientists who work on psyllids, the group to which ACP belongs, agree that this insect is probably native to parts of central and southern Asia and has been moved unintentionally on citrus into areas where it is not native. Once in these new areas, with lots of citrus to feed on, favorable year round climates, and a lack of specialist natural enemies, ACP populations increase and spread rapidly.

Part of the native range of ACP is the Indian subcontinent, and the very first study on ACP was published by two scientists Mohammad Hussain and Dina Nath in 1927 . They conducted their research on this citrus pest in the Punjab region of modern day Pakistan and India where is it was associated with declines in lemons and oranges. Hussain and Nath (1927) also reported that there were nine species of parasitoid attacking the nymphs of ACP and that parasitism of this pest could sometimes exceed 90-95% at certain times of the year. One species of parasitoid, Tamarixia radiata, an eulophid that preferentially attacks the fourth and fifth instars of ACP was reared described from specimens that emerged from ACP infesting lemon leaves in Lyallpur in 1922!! This parasitoid has been used in Florida, Texas, Mexico, the Caribbean, Central and South America for biological control of ACP.

The Punjab has a very good climatic match (about 70% similar) with the major citrus producing areas in the Central Valley of California. Biological control theory suggests that climates that are similar in the pest’s region of origin and the intended receiving range for natural enemies is important because it increases the likelihood that biological control agents will be well adapted to the climatic conditions in the area into which they could be introduced. There are basically three seasons in the Punjab; cool and foggy (October – February), hot (March-June), baking hot and humid (monsoon season July – September).

UAF Pakistan

The Central Valley is characterized by very hot dry summers and cold foggy winters (Tule fog). It is anticipated that parasitoids of ACP sourced from the Punjab of Pakistan will be well adapted to California’s citrus growing areas.

Agri Entomology

Foreign exploration for natural enemies of ACP in the Punjab of Pakistan was initiated with a trip over the period 28 August 2010 to 5 September 2011 to assess the potential for collaboration with scientists in the Department of Agri-Entomology at the University of Agriculture Faisalabad (UAF) (Faisalabad was formerly known as Lyallpur). It was quickly determined that UAF would be an excellent base for this project because it had research plots of citrus infested with ACP that were not treated with insecticides, UAF is closely positioned to Sargodha and Toba Tek Singh important commercial citrus production areas in the Punjab, and the Vice Chancellor of UAF, Dr. Iqrar Khan, a MS and Ph.D. graduate from UC Riverside (supervised by Dr. Mikeal Roose) and world leader in HLB research was extremely enthusiastic about developing a joint project between UAF and UC Riverside.

Mark and Christina Hoddle with VC Khan

Zaman taking field data

A four week trip to Pakistan over the period 11 March 2011 to 10 April 2011, resulted in the setting up of two research plots in Square 9 and PARS, both of which are UAF citrus research areas. In these two plots ACP and natural enemy population dynamics and flush growth patterns are being studied weekly on two different types of citrus, kinnow and sweet orange. Kinnow, a type of mandarin bred at UC Riverside by H.B. Frost in 1935 and introduced to UAF in 1940 and the first tree was planted in Square 9 one of our current study sites! Kinnow accounts for about 85% of citrus produced in the Punjab and it is an export crop for Pakistan. A Masters Student in Agri-Entomology, Mr. Shouket Zaman Khan was trained to do this work, and he is supervised by Dr. Mohammed Jalal Arif. At the end of this period, 80 Tamarixia radiata (24 males and 56 females) and 70 Diaphorencyrtus aligharhensis (25 males and 45 females) were returned to Quarantine at UC Riverside and used to establish colonies. All living material for this project is moved under USDA-APHIS permit and is cleared at LAX by Homeland Security Personnel before being moved to the Quarantine Facility at UCR.

Dr. Mohammad Jalal Arif working three phones

The third trip to Pakistan to look for ACP natural enemies was conducted over the period 6 June 2011 to 13 June 2011. This trip was very successful and 406 T. radiata (151 males and 255 females) and 25 D. aligarhensis (21 males and 4 females) were returned to UCR’s Quarantine facility.

The fourth collecting trip to Pakistan was completed over 28 October to 4 November 2011. From this collecting trip about 800 T. radiata and approximately 30 D. aligarhensis were brought back to UC Riverside. From all of these collections, just two parasitoids of ACP have been collected, T. radiata and D. aligarhensis. Consequently, we are questioning the validity of Husain and Nath’s (1927) claim that ACP nymphs were attacked by nine different species of parasitoid. Based on our experiences with collecting and rearing large numbers of specimens from Pakistan and from three different time periods it seems unlikely that the parasitoid fauna associated with this pest is diverse.

Shipments of natural enemies carried from Pakistan to UCR are processed in a receiving room in Quarantine. During this initial inspection phase, shipments are checked for accidental contaminants which are eliminated and destroyed immediately. Colonies of these natural enemies are set up in Quarantine at UC Riverside and are maintained as isocage lines to preserve genetic diversity. Maintaining colonies of ACP and its natural enemies in Quarantine is very difficult, time consuming, and requires meticulous attention to detail. Colonies of ACP and natural enemies are double caged, kept in secure rooms that are within secure rooms, and workers must wear coveralls which are removed in a designated changing room once work in the colonies is finished for the day.

T. radiata and D. aligarhensis are undergoing safety testing to ensure that they will pose no undue risk to the environment in California. Release of T. radiata for biological control of ACP in California is anticipated for Spring 2012 once the Environment Assessment Report has been reviewed and approved by USDA-APHIS.

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First Release of Tamarixia radiata in California for the Biological Control of Asian Citrus Psyllid

Anonymous — Mon, 20 Jan 2020 02:01:15 +0000

First Release of Tamarixia radiata in California for the Biological Control of Asian Citrus Psyllid Anonymous (not verified) Sun, 01/19/2020 - 18:01 More Blog Posts Mark Hoddle December 20, 2011

Provost and Executive Vice Chancellor of UC Riverside Dallas Rabenstein (left) and Mark Hoddle (right) made the first release of Tamarixia in Southern California.

At 11:00 am on the 20 December 2011, approximately 30-40 people assembled at the UC Riverside Biological Control Grove to participate in the first release in California of the Asian citrus psyllid natural enemy, Tamarixiaradiata. Representatives from the University of California, California Department of Food and Agriculture, Citrus Research Board, and Citrus Pest and Disease Prevention Committee were in attendance. The event was covered by local media including Riverside’s Press Enterprise. After a brief introduction and description of the problem California faces with Asian citrus psyllid, and a quick review of the approximately two year process to reach this point, Mark Hoddle invited Provost and Executive Vice Chancellor Dallas Rabenstein to make the first release of Tamarixia in Southern California.

The Issue: In 2008, Asian citrus psyllid (ACP) was first found in California. This insect feeds on citrus and close relatives of citrus. The major problem with ACP is that is spreads a bacterium that causes a lethal disease in citrus known as Huanglongbing (HLB) . There is no cure for this disease. HLB is NOT in California.
ACP is widely established in LA County and pest populations are increasing and spreading in Riverside and San Bernardino Counties. This pest is almost exclusively restricted to backyard citrus. Spray programs to control ACP are difficult and expensive, and not every infested tree can be found and treated. Additional tools are needed for controlling ACP in California and biocontrol is one of these additional control options for ACP.

An adult Asian Citrus Psyllid on a citrus leaf.

The Biocontrol Program: ACP is native to Asia and the Punjab of Pakistan and India and this area is thought to be part of the native range where this insect evolved. People have accidently moved this pest and HLB around the world through the accidental movement of infested citrus plants.
Over the last two years Mark and Christina Hoddle (Department of Entomology, University of California, Riverside) have worked in Faisalabad Pakistan looking for natural enemies of ACP. Faisalabad Pakistan was chosen for this research effort because this part of Pakistan has a very good climate match (~70-75%) with the major citrus producing areas of California which will mean the natural enemies released in California will be pre-adapted to very hot dry summers and cold foggy winters.

An ACP Natural Enemy from Pakistan: One parasitoid found attacking ACP in the Punjab of Paksitan is Tamarixia radiata. This is a very small insect that kills ACP nymphs either by parasitizing them (i.e., females eggs laid underneath ACP nymphs and the parasitoid larvae burrow into the nymph to feed which kills the pest) or by host feeding (i.e., female parasitoids stab the nymph with their ovipositor, a tube that they use to lay eggs, and they feed on the body juices that leak from these wounds. This kills the nymph too.)

An adult female Tamarixia (left) and a dead Asian Citrus Psyllid nymph with an exit hole (right) from which an adult Tamarixia emerged after successfully parasitizing it.

Quarantine Studies: Safety tests conducted by Dr. Raju Pandey in Quarantine at UC Riverside clearly demonstrated that this parasitoid posed no undue risk to California’s environment, other species of insects, or humans. A 60 page Environment Assessment Report on Tamarixia that summarized the results of these studies was prepared by Mark Hoddle and Raju Pandey for review by USDA-APHIS. On 7 December 2012, APHIS issued a permit (P526P-11-04159) authorizing the release of Tamarixia from Quarantine for establishment in California for the biological control of ACP.

The Release Event: On 20 December 2011 at 11:00am, 12 glass vials containing 186 female Tamarixia and 95 male Tamarixia (total 281 parasitoids) were opened to release the parasitoids in the Biocontrol Grove at UC Riverside. The eight colonies in Quarantine from which these parasitoids were sourced for release were tested using DNA analyses to ensure that they were free of the bacterium that causes HLB. All tests were negative for HLB indicating that the parasitoids were free of this bacterium.
The Biocontrol Grove is a repository for natural enemies that have been imported for the biological control of citrus pests (e.g., scales, mealybugs, whiteflies, etc) in California over the last 50+ years. With the releases of Tamarixia in the Biocontrol Grove, one more natural enemy is being established here to combat an invasive pest that threatens California’s agricultural prosperity.

Expected Outcomes: This release of 281 Tamarixia is the first salvo against ACP in California. Over the next year or so it is anticipated that thousands of these parasitoids from Pakistan will be mass reared and released throughout LA, Riverside, and San Bernardino Counties and other areas as the pest continues to spread. Once Tamarixiaestablishes it will move by itself to find new populations of ACP to attack and kill. The parasitoids will have the ability to enter areas to kill ACP that may be difficult or impossible to reach for pesticide applications.

Tamarixia will *NOT* eradicate ACP from California but this natural enemy should reduce the populations of ACP in California. Every ACP killed by Tamarixia will be one less pest for homeowners and commercial citrus growers to worry about.

For More Information: These websites have more information on ACP and the work in Pakistan looking for natural enemies of ACP.
http://cisr.ucr.edu/asian_citrus_psyllid.html
http://cisr.ucr.edu/citrus_greening.html
http://cisr.ucr.edu/blog/psyllids/hunting-for-natural-enemies-of-asian-citrus-psyllid-in-pakistan/

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Tamarixia radiata release video

Anonymous — Mon, 20 Jan 2020 01:53:31 +0000

Tamarixia radiata release video Anonymous (not verified) Sun, 01/19/2020 - 17:53 More Blog Posts CISR Team January 12, 2012

Christina Hoddle explains the release of Tamarixia radiata at UC Riverside. Video recorded on December 20, 2011 at University California Riverside.

For more information about Tamarixia radiata and Asian Citrus Psyllid, visit the CISR website: http://cisr.ucr.edu/asian_citrus_psyllid.html

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