One day your plants look fine and the next day aphids are sucking the life out of them! Aphids puncture the cell walls of young plants draining cells dry, spreading plant viruses and eventually killing the plant. Species and colors of aphids range from shades of green, red, brown, black and yellow and most have pear shaped bodies with tubes (cornicles) coming from the back end. Aphids cause the following damage to plants:
- new shoots become distorted and leaf edges curl
- leaves turn yellow, wilt and die
- plants become stunted
- honeydew appears on the leaves – a shiny sticky film left by aphids
- black sooty mold fungi deposits form a filmy layer on leaves, stems or fruit (fungi feeds on the honeydew deposited by the aphid)
Before deciding on the method you’ll use to kill aphids, consider that there are beneficial insects in the garden you probably don’t want to get rid of. One adult ladybug will consume up to 40 aphids per day and their larvae will eat hundreds! Other natural enemies to aphids are the adult lacewings, flower (syrphid) flies and parasitic wasps. Beneficial insects feed on nectar and pollen in plant flowers and their young devour insect pests particularly aphids.
Insecticide sprays for aphids
Tomato leaf spray will not harm beneficial insects in the garden. Make it like you’d make tea; chop tomato leaves to equal one or two cups, add to two cups water and let water with chopped leaves steep overnight. The following day, strain out leaves and add two cups water plus ‘tomato leaf tea’ to a spray bottle. Spray leaves and stems of plants including the undersides of the leaves where aphids congregate.
Garlic oil spray will also kill aphids but may harm beneficial insects and should be used with care. Mince three to four cloves of garlic and add two teaspoons mineral oil. Let the mixture stand for 24 hours, strain to remove garlic pieces and add a half litre of water. Add a teaspoon of liquid dish soap to the mix – this will be the concentrate. Before spraying plants put a couple of teaspoons of concentrate with a half litre of water into a spray bottle and apply to plants. Garlic oil may be applied by hand or sprayed on affected plants.
Soap is one of the oldest methods of dealing with insect garden pests, the key is to use the right concentration of soap in water so that plants are not damaged. Using liquid soap (not detergent) dilute 1 to 2 tablespoons in one litre of water. Mix it up in a large container then transfer to a spray bottle.
Variation using all of the above
Garlic, onion, ginger, horseradish leaves, cayenne or other hot peppers and strongly fragrant spices may be chopped (1/4 to 1/2 cup) covered with boiling water in a mason jar and allowed to steep overnight. The following day strain, add some of the insecticidal soap (above) with water to a spray bottle and apply to plants. If you don’t use it all, freeze the remaining mix.
My preference for dealing with aphids on tomato plants in the absence of ladybugs is tomato leaf spray or a visit to the garden centre for an insecticidal soap. They usually have a variety of sprays mixed in proportions safe for plants while getting rid of the aphids.
Thanks for reading! I’m interested to know if you have organic methods of dealing with aphids.