Canker Diseases in Florida Citrus. University of Florida/IFAS, Immokalee, FL

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1 Management of Psyllids and Leafminers to Slow the Spread of Greening and Canker Diseases in Florida Citrus Jawwad A. Qureshi and Philip A. Stansly University of Florida/IFAS, Immokalee, FL

2 Asian Citrus Psyllid (ACP) Diaphorina citri (Hemiptera: Psyllidae) Eggs Nymphs 5 nymphal instars M. Rogers Adult

3 Huanglongbing / Citrus Greening Disease HLB ( blotchy mottle) Micronutrient deficiency (symmetric)

4 Spread of Citrus Greening in Florida

5 Psyllid Management Objectives Extend productive life of citrus trees by reducing risk and/or rate of infection with greening. Prevent or reduce survival of psyllids Prevent or reduce movement of greening infected psyllids to new trees

6 Risk Hierarchy for Psyllid Containerized nursery plants Young Young trees High potential return Highly susceptible to greening Likely to become infected Likely to serve as sources of infection Mature Trees Least susceptible, or likely to spread greening Reservoirs for natural enemies and susceptible psyllids

7 Psyllid Management Considerations Scouting for psyllids Conservation of biological control agents Systemic insecticides Imidacloprid (Admire), Aldicarb (Temik) Foliar applications Young vs. mature trees

8 Scouting for Psyllids 1. Adults a Tap sample 2. Eggs and nymphs a Number of infested shoots a Infestation rating (1, 2 or 3). 3. Flush Density a Young shoots per quadrat a 2 quadrats/tree at random a Separate samples for resets Qureshi and Stansly. Proc. Fla. State Hort. Soc

9 Biological Control Psyllid control with naturally occurring or introduced beneficial insects Worth Protecting!

10 Important Predators Ladybeetles-Coccinellidae Larva Olla v-nigrumv Adults Curinus coeruleus Olla v-nigrumv P. Stansly Harmonia axyridis Cycloneda sanguinea M. Rogers Psyllid Nymphs

11 P. Stansly Chrysoperla spp. Important Predators Lacewings - Chrysopidae Adult Psyllid Nymphs Larvae Ceraeochrysa spp.

12 Parasitoid: Tamarixia radiata Adult Egg Larva A. Urbaneja Prepupa

13 The Psyllid Faces Sig- nificant Natural Mortality 100 Not protected Protected with cages Mortality (%) per cohort Jan Mar Apr May Jun July Aug Sep Oct Nov Dec 2006

14 Ladybeetles initially attracted to psyllid nymphs, then leave as psyllids are consumed: Cumulative Abundance of 4 Species, May Oct 2006 Beetles seen / min Age of psyllid cohort from egg to adult (days)

15 Qureshi, Stansly, Rogers & Hall 2008 Parasitoid Tamarixia radiata is established in Florida. Found in 26 of the 28 groves across 16 counties

16 Parasitism rates were low, particularly during spring and summer (< 20%) and improved during Fall (39-56%) at some locations T. radiata parasitism (%) Southwest Region Central Region Eastern Coastal Region M A M J J A S O N D J F M A

17 Incidence of Parasitism by Tamarixia radiata on Citrus in Isabela, Puerto Rico 100% 80% 60% 40% 20% 0% 17-Jun 8-Sep 18-Nov 21-Jan 21-Mar 29-Apr 8-Jun 17-Jun 1-Jul 14-Jul 29-Jul 1-Sep Pluke, Qureshi, and Stansly. Florida Entomologist. 2008

18 Release of Diaphorencyrtus aligarhensis from Guangdong China, 2007 J. Qureshi & E. Rohrig

19 Activity of Psyllid Natural Enemies in Florida: Summary An estimated 88% psyllid nymphs in the field are consumed over the year by predators, principally ladybeetles and lacewings. Predation is greatest during the growing season. The parasitoid Tamarixia radiata is widely distributed but contributes little to mortality of psyllid nymphs except possibly late season. Additional parasitoids are being sought and released

20 Compatibility with Insecticides Foliar Drench Soil Incorporation

21 Foliar Applications: Effects on Psyllid and Ladybeetles, June 2006 Assail 30 SG (0.131 lbs AI/Acre) Provado 1.6 F (0.125 lbs AI/Acre) Individuals a a b Nymphs/flush Adults/tap sample Total over 14 days after treatment a a b a b Untreated Assail Provado c Ladybeetles/20 flushes

22 Impact of Foliar Sprays during the Growing Season: Summary Psyllid protection is short term with possible long term impacts to beneficial insects. Reduced natural enemy activity could set into motion a treadmill of increasing applications to maintain control. Compatible strategies are required that conserve beneficial insects to help manage psyllids, greening, and other pests: Dormant Sprays Systemic Insecticides

23 Dormant Season Foliar Applications Effects on Psyllid,, 2007 Silver Strand North, Immokalee, FL Adults / tap sample Mar Untreated Chlorpyrifos (Lorsban, 3 lb AI/Acre) Significantly different 29- Mar 12- Apr 25- Apr 29- May 22- Jun Application Jan, Jul NS 27- Aug

24 Dormant Season Foliar Applications Ladybeetles on Treated and Untreated Trees, 2007 Silver Strand North, Immokalee, FL Beetles / tap sample Untreated Chlorpyrifos (Lorsban, 3 lb AI/Acre) Not significantly different 8-Mar 29-Mar 12-Apr 25-Apr 29-May 22-Jun 24-Jul Application Jan, 15

25 Dormant Season Foliar Applications Effects on Psyllid,, 2007 SWFREC, Immokalee, FL Adults / 32 tap samples Untreated (Small trees) Untreated (Large trees) Admire (Small trees) Temik alone (Large trees) Temik + Spray (Large trees) Mar Apr May Jun Jul Aug Sep Oct Nov Dec Applications: End of Jan 07

26 Timely Aldicarb (Temik 15G, 33 lbs/acre) Applications: Effects on Psyllid Nymphs, 2007 Silver Strand North, Immokalee, FL Nymphs developed from 1 st instar to adult on treated and untreated trees Reduction (%) * Soil applications * 20 Nov, Jan, Feb, 07 * Significantly different from control 0 Young to mature nymphs Qureshi and Stansly. Pest Management Science. 2008

27 Predators in Aldicarb (Temik 15G, 33 lbs/acre) Treated and Untreated Trees, 2007 Individuals / 64 tap samples Silver Strand North, Immokalee, FL No significant effect Soil applications Untreated 20-Nov Jan Feb-07 Spiders Lacewings Ladybeetles Qureshi and Stansly. Pest Management Science. 2008

28 Nymphs / flush Drench Applications on Young Trees: Effects on Psyllids and Ladybeetles, st application (July 21, 2006, no rain) 2 nd application (August 21, 2006), Vydate only Untreated Vydate (1.0 gal/acre) Admire Pro (9 oz/acre) Ladybeetles/min SWFREC, Immokalee, FL Ladybeetles reduced in both treatments 6-Sep 0 1-Aug 11-Aug 6-Sep 19-Sep 27-Sep 2006

29 Asian Citrus Psyllid Management Conclusions and Implications Spring flush provides unlimited food to overwintering population of psyllid resulting in a massive first generation and emigration of the pest and possible major spread of the disease. Control of overwintering psyllid adults with effective foliar applications during tree dormancy protects spring flush and provides long lasting psyllid suppression. Generalist predators are not abundant during late fall and winter and are therefore at low risk from such applications, but return in spring to help maintain psyllid control.

30 Asian Citrus Psyllid Management Conclusions and Implications Temik 15 G applied 2-3 months before spring flush and imidacloprid to young trees controls psyllids without eliminating generalist predators. Maximum protection in spring flush will reduce psyllid pressure and necessity of insecticide applications later in the year. Reduced insecticide use on mature trees during the growing season will provide refuge for natural enemies and enhance the effectiveness of ladybeetles, lacewings, parasitoids and bees.

31 Citrus leafminer Phyllocnistis citrella (Lepidoptera: Gracillariidae) Adult Egg Larva R. Duncan Damage J. Qureshi Pupa

32 Citrus Canker Disease Gottwald et al. 2002

33 Leafminer Management in Florida Again biological control is worth protecting! Strong predatory complex Several indigenous parasitoids More effective parasitoids introduced from other regions Insecticides

34 Pseudomyrmex Predators of Citrus Leafminer in Florida Sac spiders Ceraeochrysa spp. Acrobat ants Crematogaster P. Stansly

35 Indigenous Parasitoids Families: Eulophidae, Encyrtidae, Elasmidae, Eurytomidae and Pteromalidae LaSalle and Schauff 1996 Species Cirrospilus nigrivariegatus C. sp. Zagrammosoma americanum Z. multilineatum Pnigalio minio P. sp Sympiesis sp Horismenus sardus Closterocerus cinctpennis Elasmus tischeriae Catolaccus aeneoviridis Schauff et al. 1998, Pomerinke and Stansly 1998

36 Introduced Parasitoids Ageniaspis citricola From Australia in 1994 Cirrospilus ingenuus Hoy and Nguyen 1994 J. Lotz

37 Incidence of Canker and A. citricola in Commercial Groves, São Paulo, Brazil Trees (x 1,000) Infected Eradicated 100% 80% 60% 40% 20% 0% G. fausta Ci. sp H. sp El. sp A. citricola Leafminer Ageniaspis

38 Introduced Parasitoids Citrostichus phyllocnistoides From Spain in 2006 Reduced citrus leafminer infestations to non-economic levels in Spain Major role in other Mediterranean countries and in Asia Natives C. phyllocnistoides Vercher et al A. Urbaneja

39 Citrostichus phyllocnistoides Over 12,000 (4,000 females) released in SW Florida during Stansly, Qureshi, and Nguyen

40 Semielacher petiolatus Another effective parasitoid hplays a major role in Citrus leafminer control in the Mediterranean as well as its native Australia hsimilar biology to C. phyllocnistoides L. Zappala

41 The Citrus Leafminer also Faces Sig- nificant Natural Mortality

42 Ageniaspis citricola is the most effective parasitoid of Citrus leafminer

43 Leafminer Marginal Death Rate Predation Parasitism A. citricola: 8-29% Other species: 10-15% st instar larva 2nd instar larva 3rd instar larva Prepupa and pupa Total Xiao, Qureshi, and Stansly. Biological Control. 2007

44 Insecticidal Control: Drench Applications on Young Valencia Trees Untreated CLM larvae / 5 leaves / flush a bb b b a b b b b Admire Pro (14 oz/acre) Mana AG B (16 oz/acre) Platinum (13.7 oz/acre) Platinum (18.8 oz/acre) a a bb a a a a a a Days after treatment

45 Insecticidal Control of Citrus Leafminer on Grapefruit 2 4th Year 4 5th Year Boxes per Tree Boxes per Tree a a b b a a a a Admire Agri-Mek & Oil Citrus Oil Untreated

46 Citrus Leafminer Management Conclusions and Implications Biological control plays a significant role in suppression of CLM in Florida Predators are the most important contributors to the mortality of CLM Ageniaspis has performed well in Florida but is poorly adapted for dry weather Additional parasitoids such as Citrostichus are being released Semilacher, another potential candidate is being evaluated in quarantine in Florida

47 Citrus Leafminer Management Conclusions and Implications Foliar applications provide 2-3 weeks control max. Soil-applied Imidacloprid provide longer control in young trees

48 Acknowledgements Funding: Florida Citrus Production Research Advisory Council, Insecticide industry particularly Bayer Cropscience, and Dow Agroscience for large scale studies All participating growers and companies particularly Barron Collier Company for large scale studies. Dan Pool for Temik applications. B. Kostyk,, A. Arevalo,, M. Triana,, R. Riefer