1. Biorational Insecticides in the Landscape and Options for Turf Insect Pest Management
Eileen A. Buss, Ph.D.
Associate Professor & Extension Specialist
Dept. of Entomology & Nematology, UF/IFAS

2. Learning Objectives Define “biorational insecticide”
Know the differences between conventional & biorational insecticides
Know the strengths / weaknesses of the different biorational insecticides
Be able to give a range of control options to your clients

3. Traditional Insecticides (Organophosphates & Carbamates)
Broadly toxic
Affect systems common to both insects and vertebrates (e.g., nervous system)
Risk to non-target organisms (e.g., beneficial insects, fish, birds, humans)
Secondary pest outbreaks
Pest resurgences and resistance
Broad-spectrum pesticide and therefore with low target selectivity
Most are neurotoxic
Negative impact on the non-target organism
Very persistent e.g. pyrethroids
Secondary pest
Resurgence and Resistance problem
These traditional pesticides have remained in use for many decades by the vegetables growers because they had no other alternatives. The pesticide industry just was not interested in developing new alternatives because minor crop does not provide sufficient economic incentive to support initial or continuing registration.
FORTUNATELY, there is a turning point with the recent development …………

4. What is a “Biorational” Insecticide?
An insecticide of natural origin that has little or no adverse effects on the environment or non-target organisms

5. How are Biorationals Different from Conventional Insecticides?
Different modes of action
Low use rate
More selective
Short residual activity
Low risk to humans, wildlife, and environment

6. Types of Biorational Insecticides
Botanicals
Azadirachtin/neem, rotenone, sabadilla, pyrethrins/ pyrethrum, nicotine
Microbials
Bacteria, fungi, nematodes
Protozoa and viruses – not commercially available
Others
Insect growth regulators, molt accelerating compounds, soaps, oils
IGRs influence insect development, metamorphosis and reproduction - hydroprene, methoprene, pyriproxyfen, and fenoxycarb

7. Botanical Insecticides
Natural plant products extracted from commercially-grown plants
Examples: azadirachtin/neem, rotenone, sabadilla, pyrethrins/pyrethrum, nicotine
There is a perception that “natural” products must be safer than synthetic insecticides, but some botanical insecticides like nicotine can be very toxic to humans. Others, like pyrethrins, can cause sever allergic reactions in some people.

8. Azadirachtin / Neem From seeds of the tropical neem tree
Broad spectrum (e.g., caterpillars, leafminers, thrips, whiteflies, mealybugs)
Active by contact or ingestion
Feeding deterrent, interferes with molting in young insects,
Trade names: Margosan-O, Azatin, Bio-neem (used in greenhouses, landscapes)

9. Rotenone Toxic alkaloid extracted from roots of a tropical legume
Used in garden dusts, flea powders
Very toxic to fish

10. Sabadilla From seeds of the sabadilla lilly
Trade names: Red Devil, Natural Guard
No residue; breaks down quickly in light
Target pests: caterpillars, leafhoppers, stink bugs, squash bugs, thrips
Crop: vegetables, citrus, avocado, mango

11. Pyrethrum, Pyrethrins Derived from chrysanthemum flowers
Low mammalian toxicity
Rapid “knockdown” of flying insects; paralyzes CNS
Synergized by piperonyl butoxide (PBO)
Breaks down quickly in sunlight; no residual
Expensive, but widely used

12. Pyrethroids (Group 3)
Synthetic versions of pyrethrum, but with enhanced properties
Fast-acting, good knockdown
Low mammalian toxicity; target selective for insect nerves
Broadspectrum contact insecticides used against surface-feeding insects and mites (not systemic)
Usually applied at low rates on foliage or as root drenches in nurseries
Both pyrethrins and pyrethroids disrupt normal nerve function in a region of the nerve cell called the axon. Their mode of action is to inhibit the on/off switch of nerve cells, called sodium channels, by delaying the rate at which they close, or turn off. This mode of action results in uncontrolled, uninterrupted nerve firing, which results in a convulsing insect that exhibits tremors and shaking, and quickly dies.
Cause rapid paralysis of insect nervous system by changing solubility of nerve cell membrane (disrupting closure of the “sodium gates”).

13. Pyrethroids
Pyrethroids are generally not compatible with biocontrol programs (toxic to hymenopterans)
Pyrethroids have been associated with secondary pest outbreaks (e.g., spider mites), which results in more pesticide use to control those outbreaks
Pyrethrins and older pyrethroids exhibit greater toxicity at cooler temperatures; newer pyrethroids are more toxic at higher temps

14. Movement of Pyrethroids
Not very water soluble
Pyrethroids will bind to surfaces rather than run off
However, with their widespread use, several pyrethroids have been detected in California surface waters (Weston et al. 2004)

15. Microbial Insecticides
Products that contain pathogens or microbially-derived toxins or by-products that kill insects
Bacteria
Fungi
Nematodes (not really a microbe…)
Protozoa
Viruses

16. Bacterial Insecticides
Spore-forming, rod-shaped bacteria in the genus Bacillus
Commonly occur in soils
Must be eaten to be effective

17. Bacillus thuringiensis (Bt)
Bt var. kurstaki - used since 1950’s to control leaf-eating caterpillars
Produced commercially by fermentation
Very low vertebrate toxicity
Short residual in sunlight
Works better against small larvae than vs. larger ones

18. Other Bt strains are active against insects other than Lepidoptera (e
Other Bt strains are active against insects other than Lepidoptera (e.g., M-one for Colorado potato beetle control – Bt var. san diego; Bt var. israelensis to kill mosquito, fungus gnat, and black fly larvae)

19. Milky Spore Disease (Bacillus popilliae)
Dan Potter, Univ. of KY
Diseased (left) and normal (right) grubs

20. Conserve® SC (Spinosad)
Soil-dwelling bacterium, Saccharopolyspora spinosa
Contact and stomach poison
Residual up to 2 weeks
Caterpillars, thrips, fire ants
Labeled for use on greenhouses, nurseries, and all turfgrasses

21. Avid® (Avermectin) Produced from Streptomyces avermitilis Slow acting
Low mammalian toxicity
Leaf systemic
Mites and leafminers

22. Fungi
Spores grow on the insect cuticle, then hyphae penetrate the cuticle and grow inside the body, soon killing the insect
Fungus infected chinch bug (left) & whiteflies (right)

23. Metarhizium anisopliae
Called “green muscardine disease”
The cadaver’s cuticle becomes red. In high humidity, a white mold grows on the cadaver, which turns green as spores are produced.
Fungus is naturally in soil & infects insects
Infects ~200 arthropod species (used for ticks, beetles, flies, gnats, thrips), but is safe for use around mammals

24. Beauveria bassiana (Naturalis T, Botanigard)
Called “white muscardine disease”
Used for aphids, whiteflies, mealybugs, mealybugs, ticks, beetles, flies, gnats, thrips
Greatest mortality in hot and humid conditions
Fungi do not need to be ingested to work
Infected insects die within a few days to a week
Avoid tank-mixing with fungicides

25. Improving the Chance of Infection
Use of an abrasive (e.g., diatomaceous earth) along with Beauveria may increase insect mortality by weakening the insect cuticle

26. Entomopathogenic Nematodes
Microscopic, unsegmented worms
Attack various insects (e.g., soil insects, wood borers)
Enter host’s body through mouth and spiracles, release and feed on bacteria, reproduce inside insect body
Don’t damage plants – have different mouthparts

27. Entomopathogenic Nematodes
Several species (Steinernema spp., Heterorhabditis spp.) occur naturally in the soil, but some can be purchased
Some insecticides, like imidacloprid (Merit), may slow grub behavior down and make them more susceptible to nematode infection

28. Molt-Accelerating Compounds
Mimic the action of the insect molting hormone, ecdysone (Mach 2®, Confirm®)
Low vertebrate toxicity
Ingestion forces a premature, lethal molt of turf grubs and caterpillars

29. Chitin Synthesis Inhibitor
Talus® IGR (buprofezin)
Active by contact, ingestion, or vapor
Target pests: mealybugs, whiteflies, scales, leaf- and plant hoppers
Sites: greenhouse, nurseries, ornamentals, fruit and nut trees

30. Horticultural Oils Highly refined petroleum-based oils
Useful vs. small or slow-moving, soft-bodied pests, (aphids, leafhoppers, scales, overwintering eggs, mites)
May prevent gas exchange through egg membranes, clog insect mouthparts, deter feeding or egg-laying

31. Horticultural Oils Advantages: Disadvantages: Non-toxic to vertebrates
No resistance
Disadvantages:
Must contact insect with spray
No residual
Potential for phytotoxicity

32. Phytotoxicity

33. Insecticidal Soaps
Made from salts in the fats and oils of animals and plants (very safe)
Kill by disrupting insect cuticle
Contact toxicity only – no residual
Good vs. small, soft-bodied insects (aphids, caterpillars, crawlers)
M-Pede, Rose and Flower Insect Control, and Safer Yard & Garden

34. Insecticide Options for Turf Pests

35. Caterpillar Control Options
Neonicotinoids
Arena, Meridian, Merit
Combination products
Allectus (Talstar + Merit)
Aloft (Talstar + Arena)
Pyrethroids
Talstar / Onyx, Astro, Scimitar, Tempo
IGRs/Molt Accelerating Compounds
Dimilin, Mach2
Organophosphates
Carbamates
Dylox
Sevin
Anthranilic diamides
Acelepryn
Oxadiazine
Provaunt
Microbials
B.t. var. kurstaki, Conserve
* Trade names are only used as examples and are not intended as endorsements. Other products may be labeled against this pest group.

36. Chinch Bug Control Options
Neonicotinoids
Arena, Meridian, Merit
Combination products
Allectus (Talstar + Merit)
Aloft (Talstar + Arena)
Organophosphates
Carbamates
Dylox
Sevin
Pyrethroids
Talstar / Onyx, Astro, Scimitar, Tempo
Microbials
Beauveria, Metarhizium
* Trade names are only used as examples and are not intended as endorsements. Other products may be labeled against this pest group.

37. Grub Control Options Neonicotinoids Arena, Meridian, Merit
Combination products
Allectus (Talstar + Merit)
Aloft (Talstar + Arena)
IGRs/Molt Accelerating Compounds
Mach2
Organophosphates
Carbamates
Dylox
Sevin
Anthranilic diamides
Acelepryn
Microbials
Milky spore disease
Insect parasitic nematodes
Steinernema spp.
Heterorhabditis spp.
* Trade names are only used as examples and are not intended as endorsements. Other products may be labeled against this pest.

38. Mole Cricket Control Preventive:
Treat young nymphs in May/June, soon after peak egg hatch
Chipco Choice/TopChoice, pyrethroids, neonicotinoids, combination products
Curative:
Treat after damage occurs, usually summer, fall, or spring
Baits (Dursban, Advion)
Spot treatments (Orthene, others)
Many turfgrass managers apply a preventive insecticide around the time of peak mole cricket egg hatch in May or June. Some products (e.g., neonicotinoids) are not effective against larger nymphs, so timing is important. Curative treatments are applied after preventive products have broken down and damage appears. Baits are effective against mature nymphs in August and September, but should not become wet from rain or irrigation. Spot treatments may be necessary to minimize adult damage in the fall and spring.

39. If a tree falls in the forest and no one is around to hear it, does it make a sound?

40. Do insecticides work if there are no insects present to control?

41. What should we recommend?
Determine the client’s goals and any site limitations (e.g., proximity to water, lack of irrigation, steep slope)
Rule out or consider non-chemical options first
Several products may have similar efficacy against certain pests
Product cost is a major factor