Integrated Pest Management (IPM)

 

A healthy soil and balanced ecosystem are key for the successful development of your plants and the production of seeds. Mismanagement as well as a conducive environment (i,e., humid with poor airflow) will encourage the emergence of diseases, pests and other pathogens, more likely to attack crops showing signs of nutrient deficiencies or that are vulnerable. To avoid losses through contamination and pest proliferation, the garden should also be kept clean of unhealthy and diseased plants; a task that can be implemented into your roguing process. Several mechanisms can be employed to further mitigate propagation such as promoting good airflow, drip irrigation, crop rotation, biological control methods, natural sprays, bagging, as well as the use of companion plants to promote a natural, balanced, and resilient ecosystem.

Promoting good airflow

Garden rows should be oriented so they can allow and encourage a good wind circulation between them. A good recommendation is to use the prevailing winds to your advantage, coupled with an adequate row and plant spacing, which will reduce humidity and thus the emergence of pathogens. Walking paths should also be kept cleaned and covered accordingly – preferably with a low-maintenance ground cover plant or some wood chip – to prevent the proliferation of weeds and humid microclimates.

Drip irrigation

Overhead watering should be avoided as much as possible, especially during the flowering phase of the crops, as it will detrimentally impact the seed set and its quality. If head watering is necessary, doing so in the morning is preferable so the plants can dry quickly. Drip irrigation usually stands as a better solution, which will not only prevent the occurrence of diseases on flower stalks, but will also save water by watering the plants more efficiently. Ollas (clay jars) can be used as a low-tech alternative, and will be especially helpful in dry climates. Wicking beds are also a good option to consider for small-scale seed production.

Crop rotation

Crop rotation is commonly used to control pests and diseases that can become established in the soil over time. The changing of crops in a sequence decreases the population level of pests by interrupting pest life cycles and disturbing pest habitat. Plants within the same taxonomic family tend to have similar pests and pathogens. By regularly changing crops and keeping the soil occupied by cover crops instead of lying fallow, pest cycles can be broken or limited, especially cycles that benefit from overwintering in residue.

Biological controls

Selected insects and other predators that will eat or parasitize target pests can be introduced in a controlled fashion at the beginning of the growing season. This will promote diversity and encourage the emergence of other beneficial individuals and offspring, thus offering a long-term mitigation solution.

Small insect hotels placed in strategic locations can be built in order to attract and provide habitat for useful predators and animals. They can come in a variety of shapes and sizes depending on the specific purpose or insect it is catered to. Most are designed with several sections serving as nesting facilities that can offer a seasonal shelter or refuge and host pollinators. With the help of various materials such as stones, bricks, tiles and logs, insects hotels are a useful and inexpensive solution that will aid in controlling unwanted bugs in your garden. Placing nest boxes for birds may also be used to help maintain populations of particular specifies in an area.

Companion planting

Companion planting consists in planting one plant as a companion to another. This solution aims to promote diversity and balance within a garden ecosystem, creating beneficial and interactions between crops in order to increase the resiliency of the plant population. By carefully choosing which plants to place next to each other, different combinations can be found to repel or distract pests (by discouraging or deceiving them), attract desirable insects (both for pest predation and pollination), and improve environmental conditions (by providing extra nutrients, shade, or ground cover). A common companion planting combination is alliums (onions, garlics, shallots) beneficially interacting with nightshades (tomatoes, potatoes, peppers, eggplants), brassicas and carrots by repelling/distracting slugs, aphids, cabbage loopers, maggots and worms, as well as Japanese beetles.

Natural sprays

Garden pests can be repelled and controlled with the help of several natural homemade insecticides and fungicides. Those are easy to make and inexpensive, using everyday ingredients and tools. Note that spraying must be done carefully and selectively, as it might also have a detrimental effect on your local garden ecosystem and its beneficial insects. Therefore, it is good practice to test any spray on a small area of the plant before application. For best results, the solutions must be sprayed on a dry cloudy day. Common natural insecticides are vegetable oil, soap, neem oil, garlic, chili pepper, and baking-soda sprays:

Vegetable oil spray (for aphids, mites, thrips)

  • Step 1 – Mix thoroughly one cup of vegetable oil with one tablespoon of soap for every liter of water;
  • Step 2 – Spray on affected areas;

Note: The solution will block the pores of the insects’ body, leading to suffocation

Soap spray (for aphids, mites, whiteflies, bettles)

  • Step 1 – Mix thoroughly one and one-half teaspoons of organic liquid soap for every liter of water;
  • Step 2 – Spray on affected areas;

Note: The solution works similarly as a vegetable oil spray.

Neem oil spray (for most “disruptors”, larvae and eggs)

  • Step 1 – Mix two teaspoons of neem oil for every liter of water;
  • Step 2 – Spray on affected areas (can also be used preventatively);

Note: Effective against a variety of common garden insect pests, neem oil is biodegradable and is nontoxic to birds, fish, and other wildlife. It can also be used as a natural fungicide against power mildew and other fungal infections.

Garlic spray (usually used as insect repellent)

  • Step 1 – Take two bulbs, mash them and put them in a blender with a small amount of water;
  • Step 2 – Let the mixture sit overnight, then strain it into a one-liter jar the next day;
  • Step 3 – Add one-half cup of vegetable oil (optional), one teaspoon of organic liquid soap, and enough water to fill the jar;
  • Step 4 – Take one cup of the mixture, further dilute it with one liter of water, and spray on affected areas.

Chili pepper spray (usually used as insect repellent)

  • Step 1 – Mix one tablespoon of chili powder and several drops of organic liquid soap for every liter of water and spray on affected areas;

or

  • Step 1 – Blend one-half cup of peppers with one cup of water, add one liter of water and bring to a boil;
  • Step 2 – Let the mixture sit until cooled, strain it, and add extra drops of organic liquid soap;
  • Step 3 – Spray on affected areas;

Note: Make sure to keep any chili-based spray away from the eyes, nose, and mouth. Wear protection if necessary.

Baking soda spray (for powdery mildew and other fungal, foliar diseases)

  • Step 1 – Mix one teaspoon of baking soda oil with a few drops of organic liquid soap and vegetable oil for every liter of water;
  • Step 2 – Spray on affected areas (can also be used preventatively);

Note 1: Regular use of a baking soda spray on plants will eventually seep through to the soil below. Bicarbonate can accumulate in the soil, impact the nutrients in the soil, and may lead to slower plant growth.
Note 2: Thanks to their antifungal properties, a solution of honey and tea tree essential oil mixed with water can be a very efficient alternative to consider.

Bagging

Fruits (and their seeds) can be protected from insects that feed on them and lay eggs inside by placing and tying a bag around each fruit. Make sure that the bag is large enough to accommodate the fruit’s future mature size.

 

Header photo credit: Dmitry Brant (CC-BY-SA)