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Getting Rid of Basil Pests

No garden would be complete without a few residents making their homes in or around your basil plants. Some creatures can be beneficial to the garden environment while some are bad for your harvest. I have compiled a need-to-know list of some of the most common problem makers when it comes to growing basil and what you can do to get them under control.

Aphid (Image attributed to Shipher Wu and Gee-way Lin, National Taiwan University)

Aphids are small semi-transparent green (they may also be yellow, red, brown or black) insects that spread disease from plant to plant while sucking the sap from leaves, stems and flowers. Aphids mainly feed on tender new growth, causing the leaves to appear malformed. They multiply quickly and can destroy a plant quickly, but the good news is that they are fragile. A sign of the presence of aphids is ants, as ants feed off the “honeydew” that aphids secrete.

How to control them

  •  Mix 2 TBSP of liquid dish washing detergent per gallon of water and spray the infected plants with the soapy solution. For indoor plants you can wipe the leaves. Wash the soap away after treatment to avoid damaging the herb.
  • Rotenone or Pyrethrum -based pesticides – sold in various forms as an organic pesticide for the garden.
  • The SAFER alternative is to use insecticidal soap, such as the highly acclaimed Insect Killing Soap.
  • Introduce some natural enemies into the garden. Natural enemies include ladybugs, praying mantises and green lacewings.

Japanese Beetle (Image attributed to Bruce Marlin, taken at the Morton Arboretum, Lisle, Illinois, USA)Migrated from the Far East to the East Coast, these metallic green beetles can cause a lot of damage. When they eat plant foliage they leave large, uneven holes and chew marks on the plant leaves. Adults will feed during daytime when there is full sun. They will start at the top of plants and move downward as they consume the leaves.

How to control them

  • You can buy traps to catch Japanese Beetles.
  • You can control Japanese Beetles biologically by deploying Milky Spore Disease (Bacillus popilliae) to your garden. Try using Milky Spore Grub Control.
  • If the problem is severe, purchase and release live beneficial nematodes.

Leafhopper (Image attributed to user Sarefo)There are numerous species of leafhopper. These insects are generally just under a quarter-inch long, wedge-shaped and light in color, although the color may vary depending on the species. They cause damage by eating what appear to be “channels” into the leaves. They also spread viral diseases.

How to control them

  • Insect Killing Soap
  • Rotenone or Pyrethrum -based pesticides – sold in various forms as an organic pesticide for the garden.
  • Neem and horticultural sprays are also effective.

Root-knot Nematode Damage (This image is in the public domain)Root-knot nematodes are microscopic roundworms. They damage plant roots and inhibit a plant’s ability to collect nutrients and water from the soil. Symptoms of this pest may include wilting, low yield, and the leaves becoming discolored, all related to nutrient deficiency. The roots may swell as well.

How to control them

  • Often this pest can only be verified through soil testing.
  • Avoid planting in the same spot for three to four years.
  • Plant marigolds in affected spots to kill the nematodes.
  • It may help to add organic matter to the soil and perform soil solarization (cover the soil with a clear plastic tarp for several weeks during a hot period of the year to get the soil up to 140 degrees).

Slug (Image attributed to Håkan Svensson, Xauxa)Snails are relatively small at about one-and-a-half inches and they carry a shell. Slugs are considerably longer, around five inches and do not have a shell. They come in a variety of colors, including black, brown, grey, and yellow. It is obvious where these pests have been by their slimy trails. They chew holes in the foliage of the herb and leave bite marks. Slugs are most present during wet weather and come out at night to feed.

How to control them

  • Apply materials to the soil that are rough in texture. This will cause slugs to tear their skin and perish. Such products that can be used to accomplish this include: wood ashes, lime or Diatomaceous Earth Crawling Insect Killer.
  • Beer traps. Yes, slugs and snails are attracted to the yeast and will drown themselves if given the chance. Sink a shallow dish into the soil with its rim just at the soil level and fill it up with beer.

Whitefly (Image attributed to user Gaucho)The whitefly is a tiny winged insect that gather in groups, usually under the leaves of plants, and suck plant leaves until they turn yellow and fall off. They also transmit plant disease. If you brush up against your plant and see a small cloud of white flies move away then this is your problem.

How to control them

  • Insect Killing Soap
  • Yellow pest strips can be purchased which, when deployed, will attract whiteflies by their yellow color and cause them to stick to the strips. Sticky Stakes Insect Traps have a fun name and they are effective!
  • Rotenone or Pyrethrum -based pesticides – sold in various forms as an organic pesticide for the garden.