How do insects affect crops and gardens? Most people assume insects living with their plants is a bad thing, but not true! Only a small percentage of bugs are harmful to plants, while most species help protect, enrich, and pollinate them.
What Makes a Bug Helpful?
Gardeners and farmers alike usually view insects as their enemies. This is usually because their experience with insects is negative, like encounters with the infamous cutworms, cornstalk borers, army worms, potato beetles, and others. The good insects, far more numerous than these harmful specimens, stay out of sight and out of mind, doing their jobs and providing constant nourishment and protection to all plants, whether garden flowers or utility crops.
Unfortunately, these beneficial insects, many of which are necessary, are also targeted by the pesticides growers use to kill the harmful bugs or prevent infestations. This leads to poorer crops, weakens plants, and disrupts the local ecological cycles, wiping out insect species that larger animals need to feed on.
It is important for homeowners and crop-growers alike to appreciate the jobs helpful insects do. The roles differ from area to area, but the duties fall into three main categories: Insects who eat the harmful specimens, eliminating the damage they do, insects who help pollinate flowers, and insects who fertilize the soil.
Eaters
There are many types of predator insects who devour the harmful specimens that are trying to attack your plants. Some of the more famous examples include the lady beetles, which eats aphids, the dragonfly, which takes care of mosquitoes, and the green lacewing, which feeds on aphids, mealy bugs, spider mites, and other bugs harmful to crops. There are also many species of wasp that weed out these plant eaters.
Flowers are one of the easiest ways to attract the bug-hunters, since most predatory insects use flowers to congregate, find mates, lay eggs, and look for prey. The key to letting them do their work is often patience, since harmful species of bugs will grow before hunters will grow to meet it, leading to a waiting period in which the two are balancing. Eventually, the hunters will compensate, then move on when the threat is neutralized.
There are several different ways to attract these helpful predators, from making sure plants are healthy to picking out specific flowers or shrubs that the insects enjoy. If you are forced to use a pesticide to control a severe outbreak, make sure it is a bug-specific variety that will be less harmful to the insects that are on your side.
Pollinators
Other insects pass through crops, pollinating flowers while collecting the pollen for food or scavenging for mates or tasty meals. These insects are most commonly recognized as beneficial, and many farmers set out bee hives to help pollinate their fields at the proper times.
These insects, which also include butterflies and other winged varieties, thrive on healthy plants and can be encouraged by using natural compost and adding water sources for them to drink, allowing them to journey farther and pollinate more flowers in one trip. Water sources can also attract birds and frogs, which can help give your plants additional protection.
Fertilizers
This category is not relegated to centipedes and earthworms, but includes many crawling bugs that prefer to live under the shade of garden plants, such as ground beetles, pirate bugs (which also feast on the plant eaters), and syrphid fly maggots. These bugs add nutrients to the soil, do their own mini-mulching, and contribute to the soil when they die and decompose into the earth.
They can be encouraged by keeping a clean soil cover, which will serve two purposes. First, removing weeds and dead detritus will encourage the fertilizers to explore and spread farther across the soil, and second, it will remove some prime estate for plant eaters, which love to hide in weeds and decaying plant material.
Chemical Dangers to Beneficial Insects
Pesticides used to rid gardens of harmful insects are often indiscriminate, and even those that target specific pests can accumulate in the soil and plants, eventually posing a danger to other insects as well. If the pesticide works and the target species is destroyed, this can sometimes create another set of problems, since the helpful predator species will no longer have bugs to live. They will move on to greener pastures, and your plants will be left exposed for another attack.
A similar scenario occurs with generic pesticides that target all insects. The beneficial bugs are killed along with the rest, and when a new infestation occurs there are no predator species available to counteract it, so the plant eating bugs increase in numbers very quickly, unhindered by competitors or natural predation. If pesticides continue to be used, harmful insects will also build up a resistance to it, largely by eating plants that have absorbed the chemicals through their roots.
Protecting The Good Kinds
Some gardeners go so far as to plant the eggs of predatory insects to clean up pest problems, a natural and poison-free solution that takes more time to get started but will harm neither your plant nor your soil. There are tables available, such as the one available at http://www.gardenguides.com/pests/tips/beneficial.asp, which show you how many eggs to plant and offer examples of insects to use for solving specific problems, such as planting spined soldier bugs to take care of potato beetles or using predaroty mites to end their more harmful cousins, the European red mites.
The eggs can be purchased at various nurseries or even ordered online, but if it seems like too much you can choose to include helpful plants in your garden instead, varieties that will attract and protect beneficial insects. Plants like coriander, buckwheat, dwarf sunflowers and others will draw helpful bugs and can help in small quantities with only a little care needed. There are also charts available to help you decided when to grow these ally plants and what seasons they perform best in.
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