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Are Spiders a Chemical Free Way to Eliminate Pests in Your Garden?

Updated on September 22, 2015
Jumping Spider
Jumping Spider | Source

So what is your opinion?

Should we agriculture focus more on diversity rather than eradication?

See results

Introduction

Arachnids are an extremely diverse group. There are over 30,000 species of spiders and they make up only a fraction of all arachnids (Riechert, 1984). They are predators that invoke fear in humans. The very site of a small spider is enough to make some grown men whimper. We watch them build their webs with little thought to their place in the food web. This hub will give insight into how arachnids can be used as a bio-control in pest management for agricultural practices. To do this I will be referring to two studies that attempt to quantify the usefulness of arachnid species in bio-control.

Scanning electron image of a two-spotted spider mite feeding on a leaf.
Scanning electron image of a two-spotted spider mite feeding on a leaf. | Source

Study Involving Control of Strawberry Mites

Strawberries are susceptible to two phytophageus mites known as Phytonemus pallidus (strawberry mite) and Tetranychus urticae (two-spotted spider mite). When infected with these mites, the strawberry plants experience a decrease in crop yield (Alford 1972). In 1997 a group of scientists studying in the United Kingdom sought out to determine if Neoseiulus spp. showed potential to be used to control the above mentioned mites. One of the preliminary experiments in the study included infesting thirty separate strawberry plants located in a greenhouse. The temperature monitored in the green house was comparable to the temperature experienced in early summer in the United Kingdom where this study took place. The plants were then separated at random into three separate groups. There were four female Neoseiulus californicus (predatory mites) per plant used on group one. Two Female Neoseiulus californicus per plant were used on group two. Group three was not exposed. There was indication that the Neoseiulus californicus had effectively controlled Tetranychus urticae when the predator: prey ratio was from 1: 8 to 1: 11. Multiple other experiments took place from 1997 to 1999 using the two species mentioned above. Some of them used whole strawberry plants and some of them used only leaves. Many of the experiments showed a 71% to 81% reduction in the numbers of mites and their offspring (Easterbrook 2001).

Soybean Crop Field at Dusk
Soybean Crop Field at Dusk | Source

Arachnids and Soybeans

Another study was done with soybeans in the Butler County, Ohio, United States. In these studies, twelve plots of crop land measuring 60m by 70m, planted east to west, with 90 rows of soybeans were considered. Each of the twelve plots also had a 15m mowed grass edge. Though pesticides were used on the land previously, none were being used during this study. Over the course of three years 10 plots were investigated; four in 1990, three in 1991, and three in 1992. Each plot had crates placed on them. These were to provide protection to spiders during the growing season. They augmented the spider population by encouraging the spiders to flourish on these plots of land. After three years of study they were able to prove that the average mass of the dried insect carcasses found in crates placed at the different plots was positively correlated with the average mass of spiders inhabiting the crates. They were also able to prove that there was statistically less leaf damage when spider populations were augmented (Carter 1995).

The Importance of Diversity In Agricultural Ecosystems

There are a few themes in the literature that appear often. They all relate back to diversity. The predator environment has to be plentiful in not only individuals but in species. Practices must take place to ensure great predator diversity in the agroecosystem (Riechert, 1984). This may be the opposite of what the land owner was doing previously. Many commercial agricultural systems used heavy pesticides and herbicides which will affect diversity in a negative way on the land being studied (Landis 2000). Many arachnids are also specialized feeders. If you push for one arachnid species to be present on the land over another, there won’t be a consistency in your pest management program. The desired effect will not be achieved. Every experiment examined included multiple species in their study. For success when using this technique, diversity is crucial.

The Importance of Biodiversity in Modern Agriculture

Conclusions

Can Arachnids be used for pest management in agroecosystems? The two studies mentioned along with many others investigated show that they can be affective in pest management. A new question comes to mind: can arachnids be used as pest management in large scale agricultural operations? The world’s population has now reached over seven billion by United States Census Bureau estimates. It is common knowledge pesticides used in agriculture have the potential to pollute soil and water. Can we modify our agricultural better management practices to include spiders? Books have been written on the topic. They outline how to start making agricultural ecosystems more dynamic, yet it is not a widely adopted practice in the United States.

References

Alford, D. V. (1972). The effect of Tarsonemus fragariae Zimmermann (Acarina: Tarsonemidae) on strawberry yields. Annals of applied biology, 70(1), 13-18.

Carter, P. E., & Rypstra, A. L. (1995). Top-down effects in soybean agroecosystems: spider density affects herbivore damage. Oikos, 433-439.

Landis, D. A., Wratten, S. D., & Gurr, G. M. (2000). Habitat management to conserve natural enemies of arthropod pests in agriculture. Annual review of entomology, 45(1), 175-201.

Easterbrook, M. A., Fitzgerald, J. D., & Solomon, M. G. (2001). Biological control of strawberry tarsonemid mite Phytonemus pallidus and two-spotted spider mite Tetranychus urticae on strawberry in the UK using species of Neoseiulus (Amblyseius)(Acari:Phytoseiidae). Experimental & applied acarology, 25(1), 25-36.

Riechert, S. E., & Lockley, T. (1984). Spiders as biological control agents. Annual Review of Entomology, 29(1), 299-320.

United States Census Bureau. (n.d.). U.s. and world population clock. Retrieved from https://www.census.gov/popclock/

Comments

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    • kenneth avery profile image

      Kenneth Avery 3 years ago from Hamilton, Alabama

      Casandra,

      This is an excellent piece of writing. Honestly, I can easily describe it as amazing.

      I loved every word. Graphics were superb. This hub was helpful, informative and I found it very interesting.

      Voted up and all the choices because you deserve it.

      You have such a gift for writing. Keep writing no matter what.

      Sincerely,

      Kenneth Avery, Hamilton, Alabama

    • CassandraCae profile image
      Author

      Cassandra Kuthy 3 years ago from Ohio

      While I don't recommend killing them when they are in your home, you can use the fruit of an Osage orange tree to keep them out of your more social areas. I put them in panty hose and hide them in places like behind the entertainment stand and under the sinks in the kitchen in the bathroom. I see fewer of them in my house. When the osage organge gets old it just turns into a black hard ball. No mess.

    • Nell Rose profile image

      Nell Rose 3 years ago from England

      Fascinating information, even though they give us the creeps they are definitely useful for natural pest management. I remember a few years ago asking for something to kill spiders in the home, I was told that there wasn't anything to buy because spiders are useful, this shows me that they are! great hub, nell

    • vespawoolf profile image

      vespawoolf 3 years ago from Peru, South America

      This is valuable information, that arachnids are important for agriculture and protecting plants from pests. Thank you.

    • David Stone profile image

      David Stone 3 years ago from New York City

      Excellent, skilled writing. I hope to see much more from you as you build up your inventory of hubs.

    • wheelinallover profile image

      Dennis Thorgesen 3 years ago from Central United States

      In Nebraska although they may not be using it for research there are some areas where the spider population is very high in the corn fields. This is in spite of being sprayed with herbicide and pesticides.

      In some places the ant populations are also high. They also work to keep harmful insect populations lower.

    • billybuc profile image

      Bill Holland 3 years ago from Olympia, WA

      Very interesting article my new friend. Nice research, and you explained it all in a very casual voice.

    • DealForALiving profile image

      Sam Deal 3 years ago from Earth

      Fighting pests without pesticides would make for a safer ecosystem. Very insightful article!

    • CassandraCae profile image
      Author

      Cassandra Kuthy 3 years ago from Ohio

      It's true, we need to keep food webs in tact to keep pests down. It is the natural way.

    • AudreyHowitt profile image

      Audrey Howitt 3 years ago from California

      Welcome to the hub! This makes perfect sense--without spiders we would be totally infested with all kinds of pests I suspect!

    • mary615 profile image

      Mary Hyatt 3 years ago from Florida

      Welcome to HP! I found this Hub to be very informative and interesting! I just hate pesticides, I'd rather use these guys when possible!

      Voted UP, etc. and shared.

    • AliciaC profile image

      Linda Crampton 3 years ago from British Columbia, Canada

      Thanks for sharing this information. Using spiders to control pests sounds like a much better idea than using pesticides!

    • vocalcoach profile image

      Audrey Hunt 3 years ago from Nashville Tn.

      I found this hub to be quite fascinating. My own reaction surprises me as I've been both disgusted and afraid of Arachnids in the past.

      Now, after being more informed, I feel differently.

      Pesticides are dangerous and I'd like to see them abandoned. I agree with using spiders instead.

      Thanks and voted up and more along with sharing. And thanks for the follow and welcome to HP!

    • ologsinquito profile image

      ologsinquito 3 years ago from USA

      This is very good information, that spiders can be used instead of toxic pesticides.