Pest Control

Pest Control in School Gardens

Insects

Insects are beneficial to gardens in many ways, but they can also pose a threat to plants. Like other animals, some insects are herbivorous and only eat plants. Others are carnivorous and eat insects. Other insects may feed on both plants and other insects depending on the species and the stage of their lifecycle. Generally, insects that eat other insects are beneficial to the garden (ex. ladybugs, mantids, etc). Pest control strategies fall into different categories, and often gardeners incorporate multiple strategies for an integrated approach:  


Cultural Control: This involves site selection, soil health management, spacing, and plant selection to ensure a healthy crop. Healthy plants have more natural defenses against insects. 

Physical Control: Physical control involves creating a barrier (i.e. netting) to keep pests away from the crop.  

Biological Control: Biological control includes using one species to control another, either by releasing beneficial insects or using cultural control methods to attract beneficial insects. Biological control can also include disrupting pest insect life cycles by using pheromones. 

Chemical Control: Spraying pesticides that are toxic to the target/ harmful species. Always follow the directions on the package when using any kind of spray. 


Some common garden pests include: 

Aphids

Aphids feed on the sap of plants from the stem and underside of the leaves. Lettuces, other leafy greens, and peppers are particularly prone to aphids. Control option: Try a homemade, or store bought insecticidal soap. Link to Purchase 

Ants

Ants primarily cause harm by “ranching” aphids. They protect aphid colonies from predators, in order to harvest the liquid the aphids excrete after feeding. Look for ants wherever you see large colonies of aphids.  Control options: Try ant baits. These are poisons the ants gather and bring back to their colony, thus, they tend to have a more targeted effect than a spray based pesticide. Link to Purchase  

Caterpillars

Caterpillars: The larval stage of many butterflies and moths feed on the leaves of many species of plants. Cabbage moth caterpillars (pictured at left) are particularly problematic, and love plants in the brassica family (cabbage, kale, broccoli, collards, etc). All caterpillars eventually grow up to be butterfly or moths, and keep in mind that some caterpillars, such as those of the swallowtail butterfly that feed on dill, carrots, and fennel, become valuable pollinators.  

Control options: BT, a spray made from active colonies of the Bacillus thuringiensis bacteria is toxic to caterpillars without negatively affecting other insects. Link to Purchase. You can also control catapillars by covering the plants with a row cover or fine insect netting in order to prevent the moths from laying their eggs on the plants. This method is very effective at preventing caterpillars, but will not help once they are established. Link to Purchase. 

Harlequin Beetles

Harlequin Beetles: These stink bug relatives love to feed on the sap of plants in the brassica family (kale, cabbage, broccoli, etc), and are particularly active during warm weather months (summer through early fall).

Control option: Protective netting when applied immediately after planting is effective. Since these beetles are only active in the warmest months, limiting brassica plantings to the early spring and fall is also an effective form of cultural control.

flea Beetles

Flea Beetles: These tiny little beetles put pin sized holes in the leaves of arugula and other brassica plants.                                            

Control options: protective, fine mesh netting. Netting link to purchase. For long term control, purchase and apply beneficial nematodes to the soil. Link to purchase. 

Rodents, Deer, and other Mammals 


Rabbits and groundhogs love to eat a wide variety of vegetable and flower crops. In some parts of the city, deer can be destructive garden pests, as they eat most garden veggies. Rats can also be attracted to gardens by food trash, and ripe or rotting fruit. Typically leafy green vegetables will not attract rats.  


The best approach to keeping mammals from damaging the garden is to keep them out of the space with fencing or netting. Here are some simple options:

How To Install Hoops and Netting: Click Here to Watch


Below are some additional strategies that can help deter mild pest pressure. These strategies are not effective in areas with high levels of deer or groundhogs.