Beginning Gardener’s Class

1. Beginning Gardener’s Class Week 4 17 April 2017 Stephen Janak County Extension Agent – Agriculture & Natural Resources Colorado County

2. Week 3 • Insect pests • Beneficial insects • Integrated Pest Management • Understanding Pesticides

3. Benefits and Value of Insects Pollination Parasitic insects Predatory insects Improve soil

4. “Meet the Beneficials” • Predatory insects • Also, parasitic insects • Wasps

5. Vegetable IPM website • vegipm.tamu.edu • “Texas Insects” book • Local county extension agent

6. Non-chemical reduction of insect problems • Otherwise known as the IPM approach. • Uses four key strategies: • Plant genetic resistance to pests and diseases • Biological Control (beneficials) • Environmental control (favorable for plant, unfavorable for pest) • Chemical (last resort) • Least-toxic (but effective) option first. • Grow Green Fact Sheets • http://austintexas.gov/page/grow-green-fact-sheets • Diagnosis of plant problems

7. IPM approach • Plant resistance (we talked about) • Healthy plants resist insects and disease – proper fertility and water. Micronutrient sprays. • Biological control • Avoid broadcast use and use of broad-spectrum insecticides • Cultivate plants attractive to beneficials (next week) • Environmental control • Planting at the right time (early) • Sanitation • Start with clean plants

12. Proper diagnosis is Key • “Plant Diagnosis Key and Questions” • Insect, Disease, and Nutrient deficiencies can often be confused for each other. • Nutrient deficiency: change in leaf color, stunted size, occasionally crinkling of leaves, • Insect: change in leaf color (usually mottling), stunting, crinkling of leaves, leaf curl, holes, etc. • Disease: leaf curl or wilting, leaf spots, occasionally leaf holes, change in leaf color,

13. Diagnose plant nutrient deficiencies • WHERE is problem? • New growth or Old growth • MOBILITY (publication) • Leaf tissue analysis • Form • Results

15. Proper ID of insects KEY to control • Grow Green “spider mites” and “aphids” • Simple internet searches will turn up lots of results. • Instead, try searching “______ tamu” • Or “________ extension” • Or “________ university” • Check with locals (knowledgeable store employees/owners) • Also check product label for that insect listed.

16. Insect Control • Consider row covers • Large insects, small scale • Hand picking still the best • Small, soft-bodied insects, small scale • Hand picking • Small insects, large scale • Water blast • Rain

17. Least Toxic Methods • Horticultural Oils (pub) • Insecticidal soaps • Bug-Wise: Pyrethrum, Pyrethrins, Pyrethroids, Permethrin • Bt products • Bacillus thurengiensis • Others • “Bug-Wise” Insecticides for Home Garden • Neem oil • Spinosad

18. Understanding Pesticides • Just the word “Pesticide” comes with a stigma. • More-so now because “organic” is misunderstood to mean “pesticide-free” • THIS IS NOT TRUE • USDA Organic Certification Seal • Their criteria: • Free from genetic modification • Grown without conventional fertilizers and pesticides • Processed without food additives or ionizing radiation

19. Understanding Pesticides • Organic certification • 2005 study by USDA AMS found consumers believed: • It is healthier – 65% • It is safer – 70% • It is more nutritious – 46% • Secretary of Agriculture Dan Glickman: • “Let me be clear about one thing. The organic label is a marketing tool. It is not a statement about food safety. Nor is “organic” a value judgement about nutrition or quality”

20. Material toxicity and food safety • Product toxicity measured two ways: • Acute toxicity (accidents, single-dose, one-time exposure) • Chronic toxicity (long-term exposure) • Acute toxicity • Measured in LD50 • Median lethal dose or lethal concentration • Single dose that will kill 50% of population • Information from: Alison Bernstein, PhD • Neuroscientist who studies the role of epigenetics and environmental exposures. • http://fafdl.org/blog/2017/04/13/glyphosate-vs-caffeine-acute-and-chronic-toxicity-assessments-explained/

22. Chronic Toxicity • Not measured in lethality, but rather, adverse effects on health • NOAEL – No Observed Adverse Effects Level • LOAEL – Lowest Observed Adverse Effects Level • RfD – Reference Doses • EPA uses these numbers to set tolerances for all pesticides (including organic) on domestic and imported food. • The LOWER the number, the HIGHER the toxicity

24. Food safety and pesticides • To determine RfD, must find NOAEL • If NOAEL unavailable, or data incomplete, LOAEL is used. • In this case, an extrapolation is made to determine NOAEL based on LD50, half-life, how much and how often typically used. • NOAEL and LOAEL are divided by uncertainty factors to determine RfD. • Additional modifying factors can be applied (missing data)

26. Food safety and pesticides • Caffeine (Nawrot 2003) • 6 / 1000 = 0.006mg/kg/day • (UF 10 acute to chronic, 10 subchronic to chronic, 10 variability in sensitivity within population)

27. Food safety and pesticides • Caffeine (Nawrot 2003) • 6 / 1000 = 0.006mg/kg/day • 100mg caffeine per 8 oz • 0.006 x 68kg = 0.408mg caffeine • Drink two coffees per day = 200mg caffeine • Roughly 490X recommended limit if we calculated RfD for caffeine like we do for produce residues.

28. Food safety and pesticides • EPA RfD for glyphosate: 0.1mg/kg/day • EPA RfD for Caffeine: 0.0025mg/kg/day (lowest limit, children) • Caffeine 40x more toxic than glyphosate. • More next week