Neonicotinoid Insecticides for Ornamentals The Good, Bad and Ugly

Transcription

1 Neonicotinoid Insecticides for Ornamentals The Good, Bad and Ugly Catharine Mannion University of Florida, IFAS Tropical Research and Education Center

2 Neonicotinoids Insecticides Use of these insecticides has grown considerably since the forerunner of the group (imidacloprid) was first introduced in the early 1990 s Seven neonicotinoid insecticides Acetamiprid Clothianidin Dinotefuran Imidacloprid Thiamethoxam Nitempyram Thiacloprid

3 Neonicotinoid Insecticides Systemic What do We Know Effective against sucking insects but also some chewing insects Rates tend to be lower than traditional insecticides Labeled as Warning or Caution IRAC Mode of Action 4A

4 Neonicotinoid Insecticides What do We Know Act on the insect central nervous system Mode of action is similar to that of nicotine Both nicotine and neonicotinoids act on an acetylcholine receptor; but neonicotinoids act on a unique receptor in insects making it less toxic to mammals which is unlike nicotine which is more selectively toxic to mammals

5 SPECIFICITY OF NEONICOTINOIDS FOR α4β2 Neonicotinoid NICOTINIC RECEPTORS Insect IC* 50 nm Vertebrate Selectivity Ratio Acetamiprid Clothianidin 2.2 3,500 1,591 Dinotefuran 900 >100,000 >111 Imidacloprid 4.6 2, Nicotine *Concentration of neonicotinoid or nicotine that produces 50% inhibition of the nicotinic receptor (Tomizawa and Casida, 2005)

6 What are the Variables Associated with Successful Applications? Type of Plant Growing Environment (container, field, greenhouse, landscape, etc) Target Pest(s) Application Method (foliar, drench broadcast, injection, etc) Ecological Considerations (runoff, leaching, non-targets)

7 What are the Variables Associated with Successful Applications?

8 Speed of Uptake and Persistence Target pest differences Half life of the insecticide (in soil and water) UV stability Light intensity Transpiration rate Acid dissociation constant (pk a ) Octanol Water Coefficient (Log P or Log K ow ) Water solubility Soil adsorption

9 UV Stability of Neonicotinoids Slide Credit: Presentation by C. Sclar, Longwood Gardens Data obtained from published EPA registration documents (R. Fletcher)

10 pk a and Log P (Log K ow ) Values for Neonicotinoid (AI) Neonicotinoids Acid Dissociation Constant Log P Acetamiprid Clothianidin Dinotefuran Imidacloprid weak base 0.57 Thiamethoxam n/a 0.13 Slide Credit: C. Sclar; F. Byrne

11 Relative Water Solubility of Neonicotinoids Slide information courtesy C. Sclar. Longwood Gardens

12 Summary of Characteristics Neonicotinoid A.I. pk a Log P (Log K ow ) K oc Water Sol. Acetamiprid Low High Med. High Clothianidin High High Med. Low Dinotefuran High Low Low Very High Imidacloprid None? High High Low Thiamethoxam None Low Med. High Slide information courtesy C. Sclar. Longwood Gardens

13 Some Generalizations Neonicotinoid A.I. Relative Speed of Uptake Relative Rate of Persistence Acetamiprid Fast Short Mod. Clothianidin Slow (?) Mod. Long Dinotefuran Fast Short Mod (?) Imidacloprid Slow (?) Long Thiamethoxam Med(?) Fast Slide information courtesy C. Sclar. Longwood Gardens Short Mod. (?)

14 Acetamiprid Trade name: Tristar 30SG (Caution) For use on ornamental and flowering plants grown outdoors and in greenhouses, shadehouses and lathhouses Not for homeowner use Application: Foliar only

15 Arena 50WDG; Clothianidin Turfgrass, sod farms, landscape ornamentals, interiorscapes, and non bearing fruit and nut trees in the landscape Drench, broadcast, foliar Aloft G or SC contains clothianidin and bifenthrin Turf and landscape ornamentals around residential, institutional, public, commercial, and industrial buildings, parks, recreational areas, athletic fields and sod farms (specific labels for golf courses) Drench, broadcast, foliar

16 Dinotefuran Safari 20 SG; 2G For greenhouse, nursery, interiorscapes and outdoor landscapes Application foliar, broadcast, soil drench, soil injection, micro irrigation, drip irrigation, overhead irrigation, ebb and flood, trunk spray

17 Imidacloprid Merit 75WP; 75WSP, 2F, 0.5G Commercial and residential landscapes and interiorscapes Foliar and soil applications Marathon II, 60 WP, G Greenhouses, nurseries and interiorscapes Foliar and soil applications CoreTect Landscapes, interiorscapes, forested areas Soil application

18 Discus Imidacloprid Field and container nurseries Combined with a pyrethroid (cyfluthrin) Foliar, soil injection, soil drench Allectus SC Turfgrass and landscape of residential lawns, commercial, industrial, institutional, and recreational areas (Not golf courses or sod farms) Combined with a pyrethroid (bifenthrin) Foliar, broadcast, drench, soil injection,

19 Flagship 25 WG Thiamethoxam Greenhouses, lath and shadehouses, containers, field nurseries Foliar, broadcast, drench, chemigation, Meridian 25WG; 0.33G Turfgrasses on golf courses, residential lawns, commercial grounds, parks, playgrounds, athletic fields and sold farms and ornamentals plants in residential and commercial landscapes, parks, golf courses and interiorscapes Foliar, broadcast, drench, soil injection

20 Methods of Application There are numerous options on how to apply the neonicotinoids; Take advantage of the different methods Take advantage of the different formulations Fit the method of application for the site The site and method needs to be on the label Consider the methods that gets the needed result with the least negative impact on the environment/non targets

21 Ornamental Pest Management with Neonicotinoids Key ornamental pests Scales Mealybugs Whiteflies Thrips

22 Ornamental Pest Management with Neonicotinoids Examples from South Florida 1. Differences in efficacy Cycad aulacaspis scale Asian citrus psyllid 2. Differences due to host stage Diaprepes root weevil 3. Difference due to host plant Lobate lac scale 4. Avoiding unnecessary applications Ficus thrips 5. Soil versus drench Ficus whitefly 6. Insecticide rate Ficus whitefly

23 1. Examples of Differences due to Efficacy Cycad aulacaspis scale Dinotefuran and acetamiprid were more efficacious than imidacloprid Asian citrus psyllid As foliar sprays, two neonicotinoid products that also contained a pyrethroid and (Discus and Allectus) and thiamethoxam (Flagship) provided longer control than others testes Not much differences among products used as a drench Longer control with drenches versus foliar application

24 Management of Cycad Aulacaspis Scale in Florida Pest of numerous cycads Fronds eventually become brown and desiccated; ultimately causing plant death

25 Pesticide Options Oils Ultra fine horticultural Oil Oganocide Insect growth regulators Distance Foliar insecticides Orthene Malathion Safari TriStar Soil insecticides Safari

26 Management of Cycad Aulacaspis Scale

27 Control Merit drench Distance foliar Dimethoate foliar Merit foliar Organocide Dimethoate drench

28 Management of Cycad Aulacaspis Scale 100 Percent Mortality Days After Application Control Allect Merit (drench) Merit (foliar) Discus Merit (foliar+drench)

29 Management of Asian Citrus Psyllid (Diaphorina citri) on Orange Jasmine Vectors citrus greening disease Pest of citrus and closely related plants

30 2 nd spray application

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32 Percent Mortality of Asian Citrus Psyllid on Orange Jasmine control Flag 4oz Flag 6oz Flag 8oz Flag drench 4oz Flag drench 8oz 2 dat 5 dat 8 dat 12 dat 15 dat 19 day 22 day 29 day 38day 45 day 53 day 59 day 68 day 74 day

33 2. Examples of Differences Due to Stage of Insect Diaprepes root weevil Differences in efficacy of medium (5 6 th instar) larvae among 3 products (imidacloprid, imidacloprid + cyfluthrin, and dinotefuran; however, with larger larvae (9 th instar), no difference One neonicotinoid (dinotefuran) provided control of adults when applied as a drench

34 Management of Diaprepes Root Major pest of citrus, sugarcane, ornamentals, root crops Regulatory risk all stages are commonly spread on infested plant material Weevil in Florida

35 Recovered Live Diaprepes Root Weevil Larvae (5 6 th instar)

36 Recovered Live Diaprepes Root Weevil Larvae (9 th instar)

37 Percent Adult Mortality after Feeding on Foliage from Plants Treated with Insecticides

38 3. Examples of Differences Due to Stage of Insect Lobate lac scale efficacy between two neonicotinoids was different on two host plants

39 Management of Lobate Lac Scale A pest on more than 300 tropical and subtropical fruits and ornamentals Causes branch dieback and sometimes plant death in Florida

40 Management of Lobate Lac Scale in Florida Evaluated 8 weeks after 1 st application Drench application Foliar application UF/IFAS

41 4. Example of a Comparison with a Nonneonicotinoid and Avoiding Unnecessary Applications Ficus thrips No differences among products when populations were low; Similar efficacy with a non neonicotinoid insecticide

42 Ficus Thrips (Gynaikothrips uzeli) First noted in 2003 due to heavy damage on Ficus benjamina in south Florida Feeding causes sunken, reddish spots on leaves. Leaves tend to curl and fold inward. Photos: UF/IFAS MREC

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47 5. Examples of Differences Due Method of Application Ficus whitefly Soil applications provided longer control

48 Management of Ficus Whitefly (Singhiella simplex) in Florida New continental record Causes severe leaf drop; branch dieback

49 Ficus Whitefly Panic situation Continuing to spread in the landscape and nurseries Management Nursery Established whitefly program Management Landscape Homeowner (over the counter products) Commercial applicators High potential for overuse Potential for disruption of natural enemies

50 Control of Ficus Whitefly

51 Control of Ficus Whitefly

52 Control of Ficus Whitefly

53 Control of Ficus Whitefly

54 Control of Ficus Whitefly

55 Control of Ficus Whitefly

56 Control of Ficus Whitefly

57 Control of Ficus Whitefly

58 Control of Ficus Whitefly Soil and Foliar Applications

59 6. Example of Differences Due Rate of Application In this situation, there were no differences in the two products tested or in the rate that was used of each product

60 Exotic Soft Scale (Hemiptera: Coccidae) 2008 Reported from Monroe County on croton Continues to spread and now found in several southern Florida Counties New to science; it is has been described as a new genus and species Hosts Numerous ornamental and fruit host ; many native plants in Florida Photo: H. Glenn, UF/IFAS

61 Control of Croton Scale

62 Ornamental Pest Management with Neonicotinoids Very useful, important group of compounds No, they do not always work Consider the differences among the different ai s, formulations, and methods of application and use to your advantage Recognizing When, where and how to use them Recognizing added benefits Manage the popularity of these products Recognizing situations for overuse or misuse

63 Pest Alerts Web Resources University of Florida ( DOACS (

64 Catharine Mannion Research and Extension Specialist Ornamental Entomology University of Florida, IFAS Tropical Research and Education Center SW 280 th Street Homestead, FL