Arthropod Management Tests 2011, Vol. 36
doi: 10.4182/amt.2011.F10
F10 ALFALFA: Medicago sativa L. ‘CUF-101’ EFFICACY OF INSECTICIDES FOR LEAFHOPPER CONTROL ALFALFA, 2009 Eric T. Natwick University of California Agriculture and Natural Resources Desert Research and Extension Center 1050 E. Holton Rd. Holtville, CA 92250 Phone: (760) 352-9474 Fax: (760) 352-0846 E-mail:
[email protected] Martin I. Lopez
[email protected] Leafhopper (LH): Empoasca sp. Threecornered alfalfa hopper (3CAH): Spissistilus festinus (Say) The objective of the study was to evaluate the efficacy of insecticidal compounds used against leafhoppers on alfalfa grown under desert growing conditions. An insecticide efficacy trial was conducted at the UC Desert Research and Extension Center on a stand of CUF-101 alfalfa. The experimental design was RCB using four replicates with eight insecticide treatments and an untreated check. Plots were 27 ft wide by 50 ft long. Formulations and rates for each compound and test materials applied on 15 Jul at the specified rate equivalencies are listed in the tables. Broadcast applications were delivered through 17 TJ-60 11003VS nozzles using a Lee Spider Spray Trac operated at 20 psi delivering 31.4 gpa. An adjuvant, Induce (Helena Chemical Co.), was applied at 0.25% vol/vol with all insecticide treatments. Pretreatment (PT) evaluations of insect populations in each plot were conducted on 14 Jul. Post treatment evaluations were made on 17, 22, 29 Jul, at 2 days after treatment (DAT), 7 DAT, and 14 DAT. During each evaluation, ten sweeps per plot were collected with a standard 15-inch diameter sweep net. Sweep samples were bagged, labeled, and frozen for later counting of LH and 3CAH (Tables 1 and 2). Treatment means were analyzed using 2-way ANOVA and means separated by a protected LSD (P=0.05). Pretreatment numbers of LH were similar (P=0.05) among treatments (Table 1). LH means for all insecticide treatments were significantly lower than the untreated check 2 DAT, but there were no differences among the LH means 7 DAT and 14 DAT; however, all insecticide treatments had LH means that were lower than the LH means for the check for the post treatment average. There were no differences (P=0.05) among the treatment means for 3CAH on any of the sampling dates (Table 2). There were no phytotoxic symptoms observed following any of the insecticide treatments. Table 1. LH per sweep in alfalfa Treatment
Rate, product/ acre
a
b
1 DPT 2 DAT
Check -------11.0 Lorsban Advanced 16.0 fl oz 9.65 Lorsban Advanced 32.0 fl oz 13.08 Dimethoate E267 16.0 fl oz 9.50 Warrior II 1.6 fl oz 13.13 Mustang Max 4.0 fl oz 12.23 Lannate LV 32.0 fl oz 10.68 Baythroid XL 1.6 fl oz 11.08 Ambush Insecticide 6.4 fl oz 9.98
24.45a 5.98cd 17.13b 6.75cd 11.70bc 4.78cd 8.45cd 3.83d 5.85cd
7 DAT
14 DAT
2.85 0.48 1.48 1.93 1.33 0.75 3.18 1.70 2.08
3.45 2.13 1.38 2.53 1.75 2.55 1.80 1.70 2.53
PTA 10.25a 2.86c 6.66b 3.73c 4.93bc 2.69c 4.48bc 2.41c 3.48c
Means within columns followed by the same letter are not significantly different, ANOVA; LSD (P
