Texas Agricultural Extension Service
UC-025

MANAGEMENT OF INSECTS ON HERBS

Bastiaan M. Drees
Associate Professor of Entomology
and Extension Specialist

Despite accounts that many herbs and herb products can be used to repel or eliminate insect and mite pests (see Garlic Barrier section below), Texas growers report a wide variety of pests attacking their plants. Aphids, two-spotted spider mites, caterpillars such as armyworms and cabbage loopers, leafminers and whiteflies are just a few of the pests challenging Texas herb growers. Over 42 varieties/species of plants are grown as herbs. Each species/variety has its own spectrum of pests that will attack it. Unfortunately, management options are limited and no research is being conducted to address these herb production problems.

Pesticides for control of insect and mite pests of herbs are subject to the law governing all pesticides, the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). This law states that any chemical sold to control pests must be registered by the Environmental Protection Agency (EPA). A provision in the law (Section 2ee) allows for use of pesticides not in accordance with specific instructions on the pesticide label. However, the site in which those products are used must be found on the product label. This law dramatically limits the insecticides that are allowed to be used on herbs since few products contain mention of this "minor crop".

In searching for products registered for use on herbs and spices the following products have been identified:

  • Bacillus thuringiensis - Dipel® 2X by Abbott Laboratories and others): Registered for herbs, spices and mints such as basil, chives, dill, leeks and peppermint to control armyworms (lst and 2nd instar), loopers and saltmarsh caterpillars.

  • insecticidal soap - M-Pede® Insecticide by the Mycogen Corporation and others: Registered for herbs and spices including but not limited to basil, chives, dill, marjoram and sage for control of whiteflies, aphids, leafhoppers, plant bugs, spider mites and thrips.

  • pyrethrins plus piperonyl butoxide (PBO) - Pyrenone® Crop Spray by Fairfield American Corporation and others: Registered for herbs and spices, including but not limited to anise (aniseed); balm; basil; borage; burnet; camomile; caraway; catnip; - chicory; chives; clary; coriander; costmary; cumin; curry leaf; dill; fennel (Italian and sweet); fenugreek; horehound; hyssop; marigold; marjoram, sweet (oregano); marjoram, wild; mint; nasturtium; paprika; rosemary; rue; sage; savory, summer and winter; sweet bay (bay leaf); tansey; terragon; thyme; wintergreen; woodruff; and wormwood to control a wide variety of insects (including ants, beetles, caterpillars, true bugs and flies) listed on the product label.

  • azadirachtin - Align® Emulsifiable Concentrate by Agridyne Technologies Inc.: Registered for use on "herbs and spices" particularly anise, balm, basil, borage, burnet, chamomile, caraway, catnip, chives, coriander, costmary, cumin, curry leaf, dandelion, dill, fennel, fenugreek, horehound, hyssop, mint, marigold, marjoram, nasturtium, pennyroyal, rosemary, rue, sage, savory, sweetbay, tansy, tarragon, thyme, wintergreen, woodruff and wormwood, to control a variety of insects including armyworm (beet, fall, southern and yellow-striped), cabbage looper, Colorado potato beetle, diamondback moth, imported cabbageworm, western grapeleaf skeletonizer, cutworm (black, citrus and variegated), fruit tree leafroller, navel orangeworm, omnivorous leafroller, tobacco budworm, peach twig borer, leafhopper (grape and variegated grape) and mushroom fly. Azatin® EC Emulsifiable Concentrate, also from Agridyne Technologies Inc. is registered for use on outdoor and greenhouse grown "herbs and spices" for the control of sweetpotato whitefly, greenhouse whitefly, leafminers, fungus gnats, gypsy moths, western flower thrips, mealybugs, armyworms, aphids, loopers, cutworms, leafrollers, leafhoppers, webworms, spruce budworms and sawflies.

    Products containing azadirachtin are considered to be "insect growth regulators". They work by interfering with the insects'key molting hormone, ecdysone, to prevent them from molting from one life stage to the next. Egg and adult stages of insects are not affected. These products also have antifeedant properties. Azadirachtin is extracted from the seeds of the neem tree which grows in India.

  • garlic water (100%) - Garlic Barrier from Garlic Research Labs. - This unique product is registered as an insect repellent by the EPA for use to prevent pests like ants, aphids, grasshoppers, "leaf loopers", leafrollers, spiders, spider mites, thrips and whiteflies from attacking "terrestrial food crops" (fruit trees, nut trees, citrus trees, vegetables and vine crops). "Herbs and spices" are not specifically listed on the product label. No claims are made that this product kills insects and mites. The product is promoted to prevent outbreaks of these pests. Texas data supporting the manufacturers claims are presently lacking.

    Phytotoxicity. Whenever using a product or product mixture for the first time on a plant or plant's growth stage spray a few plants and observe them for several days to determine if that spray will harm the plant in any way. Look for leaf yellowing, burning, deformation or drop. Plants in flower or in stress are more likely to display phytotoxic reactions.

    There may be other products available specifically registered on one or more herbs (ie. numerous products are reportedly registered for peppermint, spearmint and parsley). Always follow closely the instructions and restrictions provided on the product's label. There may also be products, particularly 'organic' products, generally registered for insect and mite control with no particular site listed on the product label. Diatomaceous earth products are not registered insecticides for use on herbs. Use of this material and other "home made" sprays, dusts or similar treatments must be practiced with care and at your own risk.

    Due to the limited options of pesticides registered for herb production, Texas herb producers must make maximum effort to implement other Integrated Pest Management (IPM) approaches including:

    1) Start with clean plants and use pest resistant/tolerant species/varieties if available.

    2) Practice good sanitation in the production area, removing heavily infested material and clippings. Eliminate weeds and "pet" plants in and around the production area.

    3) Use exclusion using screens and other physical barriers (No-thrips screen, BugBed Environmental Screening, Econet - Anti Insect Net and others).

    4) Hand pick pests and/or use high-pressure water sprays (Water-Wand, Jet-All or others).

    5) Practice biological control methods including conservation of natural enemies and augmentive releases (applications) of predators (predaceous mites, green lacewing larvae and others), parasites (Encarsia and Trichogramma wasps and others) and insect-predaceous nematodes (Bio-SafetTM;, Entonem®, EcomasknTM, ScanmasknTM, Larvanem® and others).

    Pest suppression approaches for herb production are often labor intensive and expensive. The price of the final product must include the added cost of pest control.

    Because of the lack of available information about herb pests and their management, Texas growers are encouraged to unite and share technology acquired:

    Identification and documentation of pests encountered using identification services provided by the Texas Agricultural Extension Service is the first step.

    Sharing information regarding registered products and their sources, and effective non-chemical alternatives will do a great deal to improve pest management practices throughout the entire industry.

    And finally, become active as an industry in efforts to secure special label status for effective products through programs such as the IR-4 Program, the Texas Department of Agriculture (Section 18 and Special Local Needs (SLN, 23(c) labels) and others.


    The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Cooperative Extension Service is implied.

    Educational programs conducted by the Texas Agricultural Extension Service are open to all people without regard to race, color, sex, disability, religion, age or national origin.

    1994

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    Last modified: March 18, 1997 by Edgar Cross