What We re Learning About Neonicotinoid Insecticides, and New Insects and Insecticides for 2014 Rick Foster and Kira Nixon Department of Entomology Purdue University Neonicotinoids Bind to the nicotinic acetylcholine receptors in the central nervous system Similar mode of action to nicotine without the mammalian toxicity Effective against sucking and chewing insects Highly systemic Safety Insecticide Oral LD50 Dermal LD50 Admire* > 5000 > 5000 Platinum* > 2000 > 5000 Assail* 330 571 Imidan 147 316 > 4640 Lannate 30 34 > 2000 Capture > 5000 >2000 * = Neonicotinoid LD50 = lethal dose for 50% of the population; Expressed in milligrams/kilogram Neonicotinoid Profile Low oral and dermal human toxicity Most considered unlikely carcinogens Little or no eye irritation Little or no skin irritation Limited effects on wildlife or arthropod predators or parasites Some environmental persistence, especially in the soil Actively systemic within the plant (or animal) Neonicotinoids and Bees Most of the neonicotinoids are highly toxic to bees LD50 = 22 44 nanograms per bee 1 nanogram is 1 billionth of a gram Systemic activity of neonicotinoids moves the insecticide to the flowers where bees tend to feed Background: Neonicotinoids and Agronomic crops Most agronomic crops are treated: all corn (95+ million acres), 60-70% soybeans (40+ million acres), canola, wheat, cotton. Total of 200 million acres/year Systemic in plant tissues to protect seed, seedling and root systems. Effectiveness varies widely across pests. 1
Corn planting background Modern planters use a vacuum system to move/plant seeds Treated seeds are sticky require talc in planter to ensure uniform planting Used talc is exhausted with air during and after planting Planter cleaning demonstration Results: Planter exhaust (used talc) Extremely high concentrations of seed coatings found in used talc Seed type Thiamethoxam Clothianidin Metalaxyl Trifloxystrobin Unused talc ND ND ND ND Treated seed 1 735, 000 Treated seed 2 68,000 3,400,000 Treated seed 3 13,240,000 4,900,000 Treated seed 4 70,000 Untreated corn seed 116, 000 10,000,000 92,000 15,030,000* 263,000 131,000 ND 47,000 ND ND 66,000 50,000 503,000 313,000 * = equivalent to approx. 700,000X the contact LD50 (20 ng) Results Seed industry is moving rapidly toward reducing or eliminating the use of talc in planting operations Chemical industry is sponsoring major research projects at universities to look for ways to reduce impacts on bees Other research is continuing What About Vegetables? Galen Dively (U. Maryland) looked at various application methods on pumpkins Imidacloprid Dinotefuran Thiamethoxam Neonicotinoid Residues in Pumpkin Pollen and Nectar (ng/g) Insecticide Application Method Pollen Nectar Imidacloprid Bedding drench 4.9 c 0.4 c Transplant water (low) 36.7 b 5.7 b Transplant water (high) 60.9 ab 7.4 ab Transplant water/drip 80.2 a 11.2 a Dinotefuran Transplant water/drip 57.5 ab 9.2 a Two foliar sprays 88.3 a 7.5 a Thiamethoxam Transplant water/drip 68.0 a 9.5 a Two foliar sprays 95.2 a 8.2 a 2
Conclusions Highest residues were found in samples receiving the high rate in split applications The closer the application to planting, the lower the residues Applications made close to flowering have the potential for a significant affect on bees Our Studies 2012 Study was begun before Dively s work was published Original intent was to look at effectiveness of FarMore technology (thiamethoxam seed treatment) compared with other insecticides, including neonicotinoids on pumpkins Collected pollen from flowers and analyzed them for presence of neonicotinoid insecticides Treatment: Seed/Soil/Spray Thiamethoxam Residues in Pumpkin Pollen PPB Thiamethoxam Untreated 0.00 Untreated Seed + Platinum 18.13 Untreated Seed + Actara 4.43 FarMore Seed 2.24 FarMore Seed + Platinum 12.97 FarMore Seed + Actara 4.96 2013 STUDIES Platinum applied in transplant water at planting. Actara applied as a foliar spray prior to flowering. Neonicotinoids and Indiana Melons Control of striped cucumber beetle, aphids, leafhoppers etc. Safer, more selective and effective than some alternatives Imidacloprid, thiamethoxam, acetamiprid Problem Most neonicotinoids are highly toxic to honey bees Lethal effects Sublethal effects Altered behavior, decreased learning ability and memory, lack of coordination, inability to return home 3
Project Objectives: Determine the risks posed to honey bees by neonicotinoid insecticides applied to cantaloupe using different delivery methods. 1. Determine residue concentrations of several recommended neonicotinoids in cantaloupe pollen. 2. Couple field residue concentrations with known honey bee toxicological sensitivity. Ultimate Goal: Modify our neonicotinoid product and application method recommendations to growers to maximize insecticide efficacy while minimizing honey bee health risks. Materials and Methods Meigs Farm Throckmorton Purdue Agricultural Center, Lafayette, IN Cantaloupe variety Athena Growing Conditions: Plant April 17 th in soilless potting mix in 72 count plastic bedding trays Transplant into field May 13 th Black plastic mulch Drip irrigation Field Design Untreated Plants Treatment Chemical Trade Name Application Method 1 Control 2 Imidacloprid Admire Pro Soil bedding tray, transplanting 3 Thiamethoxam Platinum Soil transplanting 4 Imidacloprid Admire Pro Soil transplanting 5 Thiamethoxam Actara Foliar Spray June 24 6 Acetamiprid Assail Foliar Spray June 24 7 Thiamethoxam FarMore Seed treatment Sample Collection Flowers collected from 6am 9am, June 27th 1 gallon ziplock bags stored at 5 C for 2 days 4
120 100 80 12 48 decrease olfactory learning & memory, reflex response, distance moved and increased mortality Average Imidacloprid Concentration () 90 80 70 60 67 Unable to fly home Average Thiamethoxam Concentration () 60 50 40 40 30 20 20 0 1.8 +/ 0.21 87 +/ 18 96 +/ 20 Control Admire Pro Bedding/Transplant Admire Pro Transplant 10 0 0.29 +/ 0.06 64 +/ 17 76 +/ 9 0.67 +/ 0.34 Control Platinum Actara FarMore 200 180 160 140 120 100 80 60 40 20 0 No sublethal effects until 1000 Average Acetamiprid Concentration () 0.345 +/ 0.16 151 +/ 31 Control Assail Conclusions Foliar sprays of Assail should have no negative impacts on honey bees FarMore seed treatments should have no negative impacts on honey bees The use of Platinum or Admire Pro may have adverse effects on honey bees The use of Actara as a foliar spray may have adverse effects on honey bees Questions Still to Be Answered What s New for 2014 Will these results be similar in a second year? Will lower rates of Admire Pro, Platinum, or Actara result in lower residues but still provide acceptable levels of control? How long will FarMore treated seeds provide control of striped cucumber beetles and protection from bacterial wilt? Closer insecticide was added to the recommendations for control of aphids, whiteflies, and plant bugs on several crop groups Blackhawk insecticide was added to the recommendations for control of caterpillars and Colorado potato beetles on several crop groups. The threat from the invasive brown marmorated stink bug was specifically addressed for several crop groups. 5
Brown Marmorated Stink Bugs Found in Indiana First discovery in Elkhart County in October, 2010 Confirmed in 14 counties Likely present in many other locations Brown Marmorated Stinkbug, Halyomorpha halys (Stal) Why should we care about brown marmorated stink bugs? Serious pest of vegetables such as tomatoes, peppers, sweet corn, green beans, etc. Serious pest of fruit crops such as peaches, apples, grapes, etc. Pest of corn and soybeans Pest of many ornamental plants They like to overwinter inside homes They are difficult to control They stink 6
BMSB They will likely first be a problem as an invader of homes lots of interest right now I suspect that it is present in almost every county in Indiana I expect that 2014 will be the first year where we see serious crop injury Questions? 7