Not so secret garden

How good insects can help the garden

ALPENA — Bees, spiders and other insects may make many people jump from fright. But, many are there for good reason.

Insects such as honey bees, butterflies, spiders and some species of beetle are good for gardens and the Northeast Michigan ecological landscape as a whole.

Michigan State University entomologist and nematologist Marisol Quintanilla said there is great diversity in beneficial insects.

“Some insects are beneficial by predating on plant pest, for example lady bugs feed on aphids and many other plant pest. Other insects are parasitoids, and lay their eggs on or in insect pest and feed on them from the inside. Most important parasitoids are either small wasps (microhymenoptera) or belong to the fly group such as Tachinid flies. Planting a diversity of flowers can increase the number of beneficial insects,” she said.

Fellow MSU entomologist Doug Landis echoed this sentiment.

“One key to maintaining populations of natural enemies (predators and parasitoids) of crop and garden pests and pollinators is to keep a variety of flowering plants blooming throughout the season,” Landis said.

Quintanilla said there are different ecological ways to address invasive species. One way to combat some invasive weeds or bugs are nematodes. Nematodeas are microscopic roundworms which inhabit many different habitats and perform diverse ecosystem functions, she said.

“Some nematodes are plant parasites, some are animal parasites, some feed on bacteria, some on fungi, algae, or even other nematodes. Some nematodes are considered pest and others are considered beneficials. In Michigan agriculture, some of the most famous nematode pest are root lesion nematodes, northern root knot nematode, soybean cyst nematodes among several others. Plant parasitic nematodes are difficult to manage and can significantly reduce yield. There are several nematodes that are beneficials, for example there are nematodes that feed on other nematodes in the soil (predators), and there are entomopathogenic nematodes that are used a biocontrol agents for some insect pests,” she said.

Some are helpful because they help to control pest species, and people can use them in gardens.

Many beneficial insects depend on pollen and, or nectar for their energy supply, Quintanilla said.

“Some flowers are more attractive to beneficials than others, sweet alyssum, buckwheat are effective examples. Many native flowers are also very attractive to beneficials. Beneficials help crops by feeding on insect pest, in fact, some plants have strategies to attract beneficials to them in order to get help controlling their pest. Beneficials can also be involved in pollinations, besides their pest control benefits, so you can get a good two for the price of one deal,” she said.

She said there are many different ways to protect them.

“Pollinators can be protected by not applying insecticides to flowering plants, also there are insecticides that are systemic (i.e. neonicotinoids), so follow the label instructions regarding protecting pollinators if you apply these. You can also protect and benefit pollinators by having a diversity of flowers and nesting sites for them,” she said.

They also can be protected by plant diversity and nesting sites.

“There are pollinators that nest in small cavities, so you can make ‘bee hotels’ in order to increase the number of pollinators in your place. Pollinators are very beneficial in Michigan and the world. They increase yield in a diversity of crops. Some vegetable and fruit crops heavily depend in pollination for good production. Pollination can increase both size and symmetry of the fruits,” she said.

She said pollinators are in a state of decline for many reason.

“Because of invasive pest and disease such as pathogens and mites and exposure to pesticide. Other important factors in their decline is habitat loss. Some native bees and butterflies are now rare or extinct and even honey bees are in decline because of similar factors,” she said.

To increase the numbers of good insects in yards she suggests a few things.

“You can increase the number of beneficial organisms in your garden by using composts, manures, and planting cover crops. By planting a variety of plants and rotating your crops, you can increase diversity below ground and increase beneficials above and below ground,” she said.

Jordan Spence can be reached via email at jspence@thealpenanews.com or by phone at 358-5687.


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