Analysis of natural mortality and contributing factors from Diaphorina citri (Hemiptera: Psyllidae) cohorts on orange

Transcription

1 Analysis of natural mortality and contributing factors from Diaphorina citri (Hemiptera: Psyllidae) cohorts on orange Jawwad A. Qureshi and Philip A. Stansly University of Florida/IFAS, Immokalee, FL, USA

2 Asian Citrus Psyllid (ACP) Diaphorina citri Florida Citrus: (Hemiptera: Psyllidae) Eggs Asian citrus psyllid discovered Generalist predators responded Nymphs Species specific parasitoids released and 27 Adult Insecticides evaluated Huanglongbing or Citrus greening discovered - 25 M. Rogers

3 Cohort Experiments to Evaluate Psyllid Mortality Trees trimmed to induce flush and psyllid oviposition Young flushes with eggs caged on 5 year old Valencia trees for 3 days Eggs and 1 st instar nymphs counted. Treatments assigned at random.

4 Cohort Experiments - Continued Caged Not caged Sticky barrier All psyllid life stages counted every other day until death or adult emergence. Predators counted for one minute per tree every other day

5 Proportion remaining Cohort Survival Apr Jun Feb o--- Uncaged, Caged May Cohort age (Days)

6 Suppression of Psyllid Populations Mainly by Predacious Insects and Spiders Uncaged Caged 23-Jan 13-Mar 24-Apr 8-May 16-Jun 3-Jul 31-Jul 21-Aug 18-Sep 16-Oct 13-Nov 4-Dec 5-Jan 13-Feb 13-Mar 16-Apr 11-May Net Reproductive Rate (R ) Cohort initiation date (26-27) R o = Estimated production of progeny from one female psyllid

7 Predators Abundance from Sticky Barriers Blattella asahinai Aranae Cycloneda sanguinea Curinus coeruleus Olla v-nigrum Harmonia axyridis Chrysopidae Formicidae Syrphidae Anthocoridae Miridae Adults on control cohorts Larvae on control cohorts Adults on sticky barrier treatment cohorts Adults trapped in sticky barrier Larvae trapped in sticky barrier Trapped Individuals

8 Predators Abundance from Visual Observation of Foliage on Experimental Trees May 16-Jun 3-Jul 31-Jul 21-Aug 18-Sep 16-Oct 13-Nov 4-Dec 5-Jan 13-Feb 13-Mar 16-Apr No. predators / min / tree 11-May Ladybeetles Lacewings Spiders Cohort initiation date (26-27)

9 May 16-Jun 3-Jul 31-Jul 21-Aug 18-Sept 16-Oct 13-Nov 4-Dec 5-Jan 13-Feb 13-Mar 16-Apr No. ladybeetles / min / tree 11-May Ladybeetles Abundance from Visual Observation of Foliage on Experimental Trees Curinus coeruleus Olla v-nigrum Harmonia axyridis Cycloneda sanguinea Cohort initiation date (26-27)

10 Incidence of Parasitism by Tamarixia radiata in Experimental Blocks May 19-May 21-Jun 1-Jul 9-Aug 23-Aug 18-Sep 14-Nov 2-Nov 1-Dec 2-Dec 1-Jan 13-Mar 16-Apr 19-May Parasitism (%)

11 Incidence of Parasitism by Tamarixia radiata in Three Regions of Florida Parasitism (%) Southwest Region Central Region Eastern Coastal Region Mar April May June July Aug Sept Oct Nov Dec Jan Feb Mar April Qureshi et al. 28

12 Natural Mortality of Diaphorina citri Conclusions and Implications Survival was significantly reduced in the cohorts that were not protected compared to cohorts in the sleeve cages resulting in 5 to 27 fold reduction in net reproductive rate of D. citri in the unprotected cohorts attributed mainly to predation. Spiders and insect predators in the families Coccinellidae, Blattellidae, Chrysopidae, Formicidae, Syrphidae, Anthocoridae, and Miridae were observed on the cohorts or caught in sticky barriers. Spiders, the ladybeetles Curinus coeruleus, Olla v-nigrum, Harmonia axyridis, and Cycloneda sanguinea, and the lacewings, Ceraeochrysa sp. and Chrysoperla sp., were most often encountered.

13 Natural Mortality of Diaphorina citri Conclusions and Implications Tamarixia radiata parasitism rates were variable and averaged less than 2% during spring and summer and improved only in fall. Overall, natural enemies play a vital role in regulating the dynamics of D. citri populations and reducing the spread of pest and disease. Therefore, integrated control programs based on conservation of natural enemies of D. citri through judicious use of insecticides and releases of new parasitoids are needed for sustainable management of pest and disease.

14 Acknowledgements Funding: Florida Citrus Production Research Advisory Council All participating growers M. Triana