lecture 17 - 3/31/11 Herbicide Formula/ons Botany 304...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 3/31/11 Herbicide Formula/ons Botany 304 Some photographs were taken off various websites and are intended for instruc?onal purposes only Formula?ons •  Ac/ve ingredients – the actual herbicide iden?fied on the product label •  Inert ingredients – everything else: solvents, diluents, encapsula?ng materials, various adjuvants * Types of Formula?ons Liquid (Sprayable)Formula/ons 1.  Water Soluble types –  Soluble liquids (S or SL) –  Soluble powders (SP) –  Soluble granules (SG) 2.  Emulsifiable types –  Emulsifiable concentrates (E or EC) * 1 3/31/11 Types of Formula?ons Sprayable (Liquid ) Formula/ons 3.  Water ­dispersible liquids (WDL) types –  Suspension concentrates (SC) –  Aqueous suspensions (AS) –  Microencapsulated (ME) 4.  Dry formula/ons for liquid applica?ons –  WeUable powders (W or WP) –  Water ­dispersible granules (WDG, WG, or DG) –  Dry Folwables (DF) * Types of Formula?ons Dry Formula/ons for dry applica/ons 1.  Granules (G) 2.  Matrix Granules (G) – (slow release) 3.  Pellets (P) or Tablets (TB) * Types of Formula?ons All formula/ons have advantages and disadvantages and it is necessary to read the product label instruc/ons before using any of these products. * 2 3/31/11 3 3/31/11 4 3/31/11 •  Herbicide Princep Caliber 90 GROUP 5 HERBICIDE •  For weed control in certain crops •  Ac1ve Ingredient: •  Simazine: 2 ­chloro ­4,6 ­bis(ethylamino) ­s ­ triazine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90.0% •  Other Ingredients: . . . . . . . . . . . . . . . . . . . 10.0% •  Total: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.0% •  Princep Caliber 90 is a water ­dispersible granule. Ignite® 280 SL HERBICIDE ACTIVE INGREDIENT: Glufosinate ammonium*................................ 24.5%** OTHER INGREDIENTS:........................................................................ 75.5% TOTAL ………………………………………………………………………………………… 100.00% **Equivalent to 2.34 pounds of ac?ve ingredient per U.S. gallon. Calcula?ng Formula?on Requirements for Ac?ve Ingredients To determine amount of liquid herbicide required for a rate given in pounds of ac?ve ingredient per acre, divide recommended rate by pounds ac?ve ingredient per gallon stated on label. * 5 3/31/11 Calcula?ng Formula?on Requirements for Ac?ve Ingredients Example Herbicide label states 4 lbs. ac1ve ingredient per gal and recommends ½ lb. ac1ve ingredient per acre. Amount of herbicide required  ­ ½ lb/A divided by 4 lb/gal = 1/8 gal/A (product). To determine amount of dry formula?on required for a rate given in pounds (oz.) ac?ve ingredient per acre, divide recommended rate by percent ac?ve ingredient stated on label. * Calcula?ng Formula?on Requirements for Ac?ve Ingredients Example: Herbicide label states dry formula1on is 50 percent ac1ve ingredient. Two pounds of ac1ve ingredient are recommended per acre. Amount of herbicide product required – 2 lbs AI/A divided by 0.5 AI/lb = 4 lbs/A (product). * Adjuvant Use with Herbicides * 6 3/31/11 What are Adjuvants? •  Adjuvants are chemicals that either facilitate the ac?on of herbicides or modify the characteris?cs of the spray solu?ons involving these herbicides. * Adjuvant Classifica?on •  Ac?vator Adjuvants •  Spray Modifier Adjuvants •  U?lity Modifying Adjuvants •  Facilitate in wehng, spreading, dispersing, solubilizing, and emulsifying the herbicide spray solu?on on the leaf cu?cle. * Adjuvant Classifica?on Ac/vator Adjuvants •  Surfactants –  Surface ac?ve agents – the most commonly used adjuvant in herbicide applica?ons. –  Surfactants are soap based adjuvants * 7 3/31/11 Adjuvant Classifica?on Ac/vator Adjuvants •  Crop Oil Concentrate (COC) –  usually highly refined paraffinic oil free of impuri?es like unsulfonated residues or as Methylated Seed Oils (MSO) * Adjuvant Classifica?on Ac/vator Adjuvants •  Inorganic salts –  these are usually nitrogen ­based fer?lizers such as AMS or 10 ­32 ­0 that are used with water soluble herbicides to enhance their penetra?on of leaf cu?cles. * Adjuvant Classifica?on Spray Modifier Adjuvants •  modifies the spray solu?on to benefit herbicidal ac?vity or minimize environmental impact. * 8 3/31/11 Adjuvant Classifica?on Spray Modifier Adjuvants •  Spreaders  ­ causes the spray droplets to adhere to and spread on foliage •  S/cker – Its sole func?on is to cause pes?cides to adhere beUer to plant surfaces and resist “wash ­off” of the foliage. •  Spreader – S/cker – a combina?on of the spreader and s?cker proper?es. •  Thickening agent (spray drib addi/ves) – used to reduce spray drim. * Adjuvant Classifica?on Spray Modifier Adjuvants •  These adjuvants have only a small effect on herbicide ac?vity other than reducing the rate of evapora?on of the solu?on on a leaf. * Adjuvant Classifica?on U/lity Modifying Adjuvants •  An/foaming Agents – usually silicon dispersed in an aerosol can or a plas?c squeeze boUle. Kerosene or diesel fuel at about the same concentra?on can also eliminate foam. •  Compa/bility Agents – used when applying herbicides in fer?lizer solu?ons. Some herbicide formula?ons may already contain these agents. •  Buffering Agents  ­ used to increase the dispersion or solubility of herbicides in extremely alkaline or acid water. * 9 3/31/11 Surfactant vs. Detergent Agricultural surfactants are formulated to suspend herbicides in a solu?on. Household detergents are formulated to precipitate soil from the aqueous solu?on. * How Surfactants Work •  Surfactants contain both lipophilic and hydrophilic groups within the same molecule –  This greatly enhances the penetra?on and effec?veness of foliar applied herbicides by reducing the surface tension of the aqueous spray solu?on. –  Allows for improved coverage, removal of air films between the spray and the leaf surface, increase the permeability of the leaf cu?cle or plasma membranes, act as a humectant, and induce stomatal entry. * 10 3/31/11 How Surfactants Work Surface Tension •  the imbalance of energy resul?ng from surface molecules not having like neighboring molecules interac?on giving rise to a “skin effect” or surface tension •  Surface tension is related to an excess energy localized on the surface of a droplet and is designated as dynes/cm (energy per unit area). Water has a surface tension of approx. 72 dynes/cm. With the addi?on of 0.01 to 0.05 w/v surfactant to the solu?on the surface tension can decrease. * How Surfactants Work Surface Tension •  The lower the contact angle and the lower the surface tension of the liquid, the weUer the solid surface becomes. •  The addi?on of 0.01 to 0.05 w/v surfactant to an aqueous solu?on can lower the surface tension from 72 dynes/cm to approx. 25 to 30 dynes/cm and lower the interfacial tension from 40 to approx. 10 dynes/ cm, greatly increasing the detergency of a surfactant. * 11 3/31/11 12 3/31/11 13 ...
View Full Document

This note was uploaded on 04/03/2011 for the course BTNY 304 taught by Professor Staff during the Spring '08 term at Purdue University.

Ask a homework question - tutors are online