Effective and Sustainable Insecticidal Control of Citrus Leafminer, Phyllocnistis citrella (Stainton Lepidoptera: Gracillariidae)

Effective and Sustainable Insecticidal Control of Citrus Leafminer, Phyllocnistis citrella (Stainton Lepidoptera: Gracillariidae)

Report Date: 04/13/2014
Project: 601
Category: ACP Vector
Author: Philip Stansly
Sponsor: Citrus Research and Development Foundation

Optimization of CLM pheromone trap deployment was evaluated at 3 densities (1 trap per acre, 1 trap per 3 acres and 1 trap per 5 acres). The total number of CLM captures was similar at all densities tested (F = 0.26; df = 2, 52; P = 0.77). CLM flight activity followed similar patterns among the three trap densities tested (1 trap per 0.40 ha and 1 trap per 1.21 ha: R = 0.93, P < 0.0001; 1 trap per 0.40 ha and 1 trap per 2.02 ha: R = 0.85, P < 0.0001; 1 trap per 1.21 ha and 1 trap per 2.02 ha: R = 0.89, P < 0.0001). These results showed that 1 trap per 5 acres is sufficient to obtain reliable moth counts upon which to base management decisions. A manuscript was submitted to the Journal of Economic Entomology. LD50 and LD80s for some commonly used insecticides for management of citrus pests in Florida were calculated for a susceptible CLM colony. These values are being used to evaluate possible resistance to the tested insecticides in CLM field populations. Larvae and adults from the susceptible colony were exposed for 48 h to different doses (0; 0.01; 0.03; 0.1; 0.3; 1; 3; 10; 30; 50; 100, 300, 600 and 1000 ppm) of the following insecticides: Actara 25WG, Agri-Mek 0.15EC, Cyazypyr, Danitol, Delegate WG, Dimethoate, Intrepid 2F and Micromite 80WGS. The following baselines have been obtained so far for their active ingredients against larvae: Actara (thiamethoxam) LD50=2.813 (CL95: 1.07-6.46) ppm, LD80=619.176 (CL95 199.10-3100.06) (n = 681; .2 = 3.81; d.f = 7; Heterogeneity = 0.76); Agri-Mek (abamectin): LD50= 0.097 ppm (CL95: 0.05-0.16), LD80=2.61 ppm (CL95: 1.41-6.04) (n = 743; .2 = 2.03; d.f = 5; Heterogeneity = 0.41); Cyazypyr (cyantraniliprole): LD50=49.55 ppm (CL95: 18.36-129.61), LD80=27,94 (CL95: 6,19.4-0,29E+06) ppm, (n = 1,021; .2 = 2.22; d.f = 5; Heterogeneity = 0.44); Delegate (spinetoram): LD50=3.56 (CL95: 0.16-20.92), LD80= 201.83 (CL95: 31.70-53761.1) ppm (n = 859; .2 = 19.43; d.f = 5; Heterogeneity = 3.88); for Dimethoate (dimethoate) LD50=1.56 ppm (CL95: 0.15-56.31) and LD80=497.45 ppm (CL95: 22.27-0.37E+09) (n = 546; .2 = 13.07; d.f = 6; Heterogeneity = 2.18); and Micromite (diflubenzuron): LD50=88.32 (CL95: 20.69-246.69) LD80=1800.5 ppm (CL95: 522.84-75810.00), (n = 714; .2 = 10.31; d.f = 5; Heterogeneity = 2.06). A different bioassay technique is being developed for Intrepid. After testing 309 larvae with Danitol, a dose of 600 ppm only resulted in larval mortality of 52%. Due to the high a.i. rates used and low mortality values, no higher doses will be tested with this product. LD50 and LD80 for Delegate, Intrepid and Micromite are being currently being estimated for adults (n = 487, n = 703, n = 381 individuals already tested respectively). CLM larvae were collected for testing from 5 commercial citrus groves with different ACP and CLM insecticide management programs: Bob Paul, Moreno Tanner Road, Silver Strand B9, Duda and PTG. Potential resistance to Agri-Mek in these field populations was assessed by obtaining mortality rates from exposure to the previously obtained LD80 for this product, 0.097 ppm. Larval mortalities thus obtained were 0.76 (n = 33), at Bob Paul, 0.76 (n = 44) Tanner Road, 0.70 (n = 80) at B9, 0.82 (n = 44) at Duda, and 0.80 (n = 50) at PTG. Thus, mortality In all cases was similar to that observed in the laboratory susceptible colony (0.80) indicating no measurable resistance to this product yet in the field populations tested. More individuals and sites will be tested for Agri-Mek and other insecticides this spring and summer.


Your browser does not support pdfs, click here to download the file.