United States and many other countries led to an increased need for alternative herbicide programs including tank mix of herbicides with different mode of action ( Beckie, 2006 ). Currently, 21 weed species have evolved resistance to glyphosate worldwide
Megh Singh, Mayank Malik, Analiza H.M. Ramirez and Amit J. Jhala
Christian M. Baldwin, A. Douglas Brede and Jami J. Mayer
in turfgrass have documented the benefits of tank mixing herbicides, PGRs, and N sources. Jeffries et al. (2013) noted beneficial effects of tank mixing an early gibberellic inhibiting PGR, paclobutrazol (PB), with a photosystem II
Yang Gao and Deying Li
granular forms to soils. Additionally, spraying fertilizer along with other chemicals as a tank-mix allows for reduction in labor, machinery, and energy. However, foliar application requires repeated applications, especially macronutrients, to meet the
Daniel Warnock* and Raymond Cloyd
Greenhouse managers tank mix pesticides to broaden the spectrum of pest control, and reduce pesticide and labor costs. However, the effect of tank mixing an assortment of pesticides on efficacy to control pests has not been documented. This study assessed how tank mixing commercially available insecticides and miticides in two-, three-, and four-way combinations impacts the control of western flower thrips (WFT), Frankliniella occidentalis in greenhouse experiments and a laboratory bioassay. The pesticides screened were spinosad, abamectin, bifenazate, azadirachtin, and imidacloprid. Each pesticide was applied at the label-recommended rate. In the greenhouse experiments, transvaal daisy (Gerbera jamesonii) and lisianthus (Eustoma grandiflorum) flowers were inoculated with 25 adult WFT, and then flowers were sprayed with the designated treatments. After 72 hours, flowers were emasculated to assess the numbers of live and dead WFT. In the laboratory bioassay, chrysanthemum (Dendranthema grandiflora) leaf disks, treated with each pesticide and all tank mixes, were exposed to 15 adult WFT. The numbers of live and dead WFT were assessed after 48 hours. For all three experiments, no antagonistic tank mixes were identified. All treatments with spinosad, including the individual application and tank mixes, resulted in high mortality of WFT based on the numbers of live and dead WFT recovered. Our data suggest that tank mixes of spinosad with the other pesticides tested do not affect the efficacy of spinosad in controlling WFT. This information is important to greenhouse managers who want to tank mix pesticides and still control WFT in addition to the other plant-feeding arthropods found in greenhouses.
F.S. Davies, M.W. Fidelibus and C.A. Campbell
An experiment was conducted to determine if gibberellic acid (GA; ProGibb, Abbott Labs) can be mixed with Aliette or Agri-Mek and oil to reduce application costs, without reducing GA efficacy, and if Silwet and Kinetic adjuvants enhance GA efficacy. Five tank mixes were tested along with a nonsprayed control. The tank mixes included: 1) GA, 2) GA + Silwet, 3) GA + Kinetic, 4) GA + Silwet + Aliette, and 5) GA + Silwet + Agri-Mek + oil. All compounds were applied at recommended concentrations. In September, ≈24 L of each tank mix was applied with a hand sprayer to mature `Hamlin' orange trees [Citrus sinensis (L.) Osb.] on sour orange (Citrus aurantium L.) rootstock. Peel puncture resistance (PPR), peel color, and juice yield (percent juice weight) were evaluated monthly between Dec. 1997 and Mar. 1998. On most sampling dates the fruit of treated trees had higher PPR and were less yellow in color than fruit from control trees. However, in Jan., fruit treated with GA + Silwet and GA + Kinetic had greater PPR than other treatments. In Feb., fruit treated with GA + Silwet + Agri-Mek + oil had the lowest PPR. The effect of the different tank mixes on juice yield was usually similar to the effect of the tank mixes on PPR and peel color. On 8 Jan. 1998, fruit from trees treated with GA alone yielded significantly more juice than fruit from control trees. On 24 Feb. 1998, fruit from trees treated with GA alone yielded more juice than fruit from the other treatments. Thus, GA efficacy is generally not reduced by these tank mixes, nor improved by adjuvants.
Frederick S. Davies, Craig A. Campbell and Matthew W. Fidelibus
It is desirable to mix gibberellic acid (GA3) with other commonly applied materials to reduce application cost. However, applying GA3 with some compounds can reduce its efficacy or cause phytotoxicity. We conducted experiments in 1997-98 and 1998-99 to determine if GA3 (ProGibb) can be tank-mixed with fosetyl-Al (Aliette), or avermectin (Agri-Mek) and oil, without reducing GA3 efficacy. In addition, we compared Silwet and Kinetic adjuvants for enhancement of GA3 efficacy. Five tank mixes were tested along with a nonsprayed control. These included 1) GA3; 2) GA3 and Silwet; 3) GA3 and Kinetic; 4) GA3 Silwet, and fosetyl-Al; and 5) GA3, Silwet, avermectin, and oil. All compounds were applied at recommended concentrations. In September 1997 or October 1998, about 2.5 gal (9.5 L) of each tank mix was applied with a hand sprayer to 14- or 15-year-old `Hamlin' orange (Citrus sinensis) trees on sour orange (Citrus aurantium) rootstock. Peel puncture resistance (PPR), color, and juice yield (% juice weight) were evaluated monthly between December 1997 and March 1998, and December 1998 and January 1999. In both years, fruit of treated trees usually had higher PPR and were less yellow in color than fruit from control trees. There were tank mix effects on juice yield in January of both seasons and February 1998. Gibberellic acid was most effective at enhancing juice yield when applied singly or with avermectin and oil. In both seasons there were dates when GA3 applied singly was superior at enhancing juice yield than a tank mix of GA3, Silwet and fosetyl-Al, indicating that GA3 was incompatible with fosetyl-Al. Neither Kinetic nor Silwet adjuvants consistently enhanced GA3 effects on peel quality or juice yield over GA3 alone.
Martin L. Kaps and Marilyn B. Odneal
Preemergent herbicides were applied to vineyards in the southcentral Missouri Ozark region. These were applied at full label rate in the fall or in the spring, at half rate in the fall and again in the spring, and as tank-mixes in the spring. Days of acceptable annual weed control (30% or less cover) beyond the untreated control were determined for these application methods over three years. The fall applications were effective at controlling winter annual weeds and early summer annual weed growth the following season. By mid summer the fall applied preemergents lost residual activity. Splitting the label rate between fall and spring was no better than a full rate spring application at increasing the days of acceptable summer annual weed control. Single preemergent spring application performed as well as tank-mixes.
Martin L. Kaps and Marilyn B. Odneal
Spring vs. fall plus spring (split) herbicide application times and single vs. tank-mix spring herbicide applications were compared as a means of extending summer annual weed control in vineyards. About 30% of the nontreated control areas were weed-covered by April or May of each of 3 years. Most treatments gave 60 or more days of acceptable annual weed control (≤ 30% cover) beyond the nontreated control. Fall plus spring application of diuron, norflurazon, or simazine at the half-label rate did not increase the days of control over spring application alone at the full-label rate. The tank-mixed herbicides diuron, norflurazon, and oryzalin in combinations of any two at the half-label rate were as effective as the full-label rate of these herbicides used alone. Weed control by oxyflurofen or simazine was extended by tank-mixing with oryzalin (half-label rates). Chemical names used: N -(3,4-dichlorophenyl) -N,N -dimethylurea (diuron); 4-chloro-5-(methylamino)-2-(a,a,a-trifluoro-m-tolyl)-3(2 H) -pyridazinone (norflurazon); 3,5-dinitro-N4,N4-dipropyl-sulfanilamide (oryzalin); 2-chloro-l-(3-ethoxy -4-nitrophenoxy)-4-(trifluoromethyl) benzene (oxyfluorfen); and 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine).
Frank J. Peryea, Denise Neilsen and Gerry Neilsen
The recommendations for boron (B) sprays in deciduous tree fruit orchards have changed little over the past 50 years. We conducted two 3-year field studies evaluating the effect of two modifications to the existing recommendation for B maintenance sprays on apple (Malus ×domestica) tree nutritional status. A widely recommended Na polyborate-based commercial B spray product was used as the B source. Postbloom sprays of B applied at the recommended annual B maintenance rate of 0.56 kg·ha-1 to `Scarlet Gala' apple trees consistently increased fruit B concentration but had a weaker effect on leaf B concentration in early August, the recommended timing for sampling leaves for mineral element analysis. Applying half or all of the annual B maintenance rate in a spray at the pink flowering stage increased flower cluster and early-season leaf B concentrations as well as having positive effects on fruit and leaf B concentrations. The pink sprays increased flower cluster Na concentration but had no effect on leaf and fruit Na concentrations. In the second study, one-quarter of the annual B fertilizer requirement was tank-mixed with each of four biweekly CaCl2 sprays applied starting in early June for bitter pit control. This treatment consistently increased `Scarlet Gala' fruit B concentration but had a lesser effect on August leaf B concentration. It did not interfere with fruit Ca status, and increased both fruit and leaf Na concentrations. Leaf Na concentration in all treatments was substantially lower than levels associated with specific Na toxicity of deciduous fruit trees. The results of these experiments indicate that applying B sprays at the pink flowering stage timing and tank-mixing B with CaCl2 sprays applied for bitter pit control are useful practices to enhance B spray efficacy and convenience of application.
Darren E. Robinson, Kristen McNaughton and Nader Soltani
black nightshade. Dimethenamid-p is not currently registered in pepper but could be an effective option to control troublesome weeds for pepper growers in Ontario. It would also be of significant benefit to growers in Ontario to have a tank mix to