Insects in Winter - Part One

Insect are cold-blooded animals and respond to cooling temperatures in a variety of ways. Mammals can generate their own heat and have the advantage of being large. Insects are small and do not have body fat for insulation from the cold and do not produce their own heat. However, they do have several general strategies which they can employ such as or dealing with winter.  One of the most interesting means that insects use to survive winters is physiologic.

Diapause

Diapause is a suspension of development that can occur at the embryonic, larval, pupal, or adult stage, depending on the insect species. In some species, diapause is optional and occurs only when induced by environmental conditions; in other species the diapause period has become an obligatory part of the life cycle.

Some species of insects over winter in the adult stage and avoid freezing damage to their body by making a sort of biologic antifreeze material. These insects synthesize compounds such as sugars and proteins which depress the freezing point. These chemicals are called cryoprotectants, such as glycerol - similar to the stuff we pour down our sinks to prevent freezing! As temperatures increase, cryoprotectants quickly decrease. Some insects, like many plants, undergo a cold-hardening when shorter days and cooler temperatures occur. The mechanisms providing over winter cold- hardiness results from a combination of supercooling and the insect- manufactured cryoprotectants. Some Alaskan insects can survie temperature as low as  -76 degrees F.


References

Danilevskii, A. S. 1965. Photoperiodism and Seasonal Development of Insects. Oliver and Boyd, Edinburgh. 

Nijhout, H. F. 1994. Insect Hormones. Princeton University Press, Princeton. 

Tauber, M. J., Tauber, C. A., and Masaki, S. 1986. Seasonal Adaptations of Insects. Oxford University Press, Oxford. 

Web Links

Developmental Biology

Insect Winter Survival Strategies

Insect Overwintering

Fall Weeds

Fall is the best time to control dandelions and other perennial weeds, such as ground ivy. In fall, the plant begins moving nutrients to the roots for storage instead of to upper plant parts for continued growth. If herbicides are applied at this time, the chemicals are transported to the roots along with the nutrients, killing the entire plant instead of just the parts above the soil surface.

The best control measures to use depends largely on correctly identifying the weed present, but one of the keys to controlling weeds effectively is making herbicide applications at the right time of year and for many broadleaf, perennial weeds like violets, ground ivy, and dandelions fall is an excellent time to get them under control.  Fall control of annual weeds like crabgrass, foxtail, etc. is not necessary. These weeds will die during the winter and do not germinate from seed until spring, making fall control unneccesary.

Many winter annual weeds, like field pennycress, shepherdspurse, chickweed and henbit, should also be targeted for controlled in the fall. Winter annual weeds germinate in fall, grow into a small rosette then overwinter and resume growth in early spring. A fall broadleaf pre-emergent application, such as Preen (trifluralin), Surflan, Pendimethalin or Dimension, should be applied in the fall to prevent weed seed germination, just as it does in the spring.

Before applying any herbicide, always have the weeds identified and follow the manufacturer's directions.  Use caution when applying herbicides around landscape beds since accidental spraying or spray drift can damage shrubs and ornamental plants.

Additional Information

New Jersey Weed Gallery - Rutger University

Henbit Information - UC Davis

Shepard's Purse - University of Illinois

Pennycress - Virginia Tech

Ground Ivy - Virginia Tech

Borax on Ground Ivy: Boon or Bane? - Iowa State University

Harvest of Trial Crops at Burlington County Ag Center

A sure sign that fall has arrived was the recent harvest of crops from the Burlington County Agricultural Center.  The crops were planted as a field trial for Rutgers University and are grown in research plots that are evaluated for their growth characteristics.  To find out what's in season throughout New Jersey this fall, visit either the Rutgers Jersey Fresh Information Exchange page or the NJ Department of Agriculture - Jersey Fresh page.

White Grubs

Recently, while walking in the neighborhood, I came across a number of white grubs crawling on a drive way.  While it may be a little too late to treat for grubs this fall, we thought it would be interesting to post this short video and some general information about white grubs.

White grubs (Order Coleoptera, Family Scarabaeidae) are 1/2 to 1-1/2 inches long, have three pairs of legs near the head, and characteristically rest in a C-shaped position. Their heads and rear ends are brown. Green June beetle grubs crawl on their backs with their legs up. Grubs can be identified by the pattern of spines (rasters) on the rear ends. It is important to know the kind of grub in order to know when to treat.

Generally, the procedure for treating for white grubs is:

• Determine the extent of your grub infestation


• Identify the Grub Species


• Select a Control Method


• Treat in the Fall

Not all lawns have grub infestations that warrant control. Lawns differ in susceptibility to white grubs because of differences in grass species, soil health, irrigation, amount of sun or shade, traffic, etc. A dense stand of grass with a healthy root system can generally tolerate up to 10 grubs per square foot.   Please read the resource cited below to obtain additional information on how to control white grubs.

Additional Information

Insect Management in Turf Grass: White Grubs

White Grub Identification

What's going on here?

Soybean field

Have you ever driven along a country road and seen fields similar to the photo above? The fields like the one show in the photo are soybean fields.

Soybeans(Glycine max) are an annual legume of the Fabaceae family. They are smooth, round beans similar to the size of peas. Soybeans are usually planted each spring, and they grow in pods on bushy, green plants.

Soybean close up (Photo by M. Nash)

In the fall, the soybeans dry out, turn brown and are harvested. After harvest, the beans are crushed to separate the soy protein from the soybean oil. Soy protein is used in food products and to feed animals.

Soybeans ready for harvest

The first domestication of soybean has been traced to the eastern half of North China in the eleventh century B.C. or perhaps a bit earlier. Soybean has been one of the main plant foods of Asia along with rice, soybeans, wheat, barley and millet.

The first use of the word "soybean" in U.S. lit­erature was in 1804. However, it is thought that soybean was first introduced into the American Colonies in 1765 as "Chinese vetches" . Early authors mentioned that soybeans appeared to be well adapted to Pennsyl­vania soil. An 1879 report from the Rutgers Agri­cultural College in New Jersey is the first reference that soybeans had been tested in a scientific agri­cultural school in the United States.

Some of the benefits of soybeans:

• Soybeans can produce at least twice as much protein per acre than any other major vegetable or grain crop, 5 to 10 times more protein per acre than land set aside for grazing animals to make milk, and up to 15 times more protein per acre than land set aside for meat production.
• Soybeans are used in the five major markets currently dependent on petroleum products including: plastics, coatings, and ink, adhesives, lubricants, and solvents.
  
• Approximately 98 percent of the soybean meal that is crushed is further processed into animal feed.
• World soybean production has increased by over 500 percent in the last 40 years.
• In 2011, U.S. farmers planted 74.97 million acres of soybeans – the sixth highest total as tabulated by the USDA.
• About 85 percent of the world’s soybeans are processed, or crushed, annually into soybean meal and oil.
• When used as an ingredient, soy can often improve the functional properties of foods.  For instance, fried donuts absorb less fat, and white bread appears whiter.
• Textured soy protein used as a meat alternative has the texture of meat but has no cholesterol and little saturated fat.
• When compared to meat proteins – the cost per pound is significantly less and you get double the volume when you rehydrate it – so is half that cost!
• Soy is an excellent source of a complete protein which is unique among plant sources.
• There is evidence suggesting that exposure to soy during childhood and/or adolescence reduces breast cancer risk later in life.

Now, when you pass one those fields of brown pea like pods you'll know the plants that were growing there and appreciate their significance.


Additional Information

Natioanl Soybean Research Laboratory

Cooking with Soy

Soybean History

Soybean Growth and Development

When Corn Tastes like a Mushroom

Recently, one of members found something special when she purchased corn at a market.  The surprise? Corn smut!  She purchased some fresh ears of corn from a market and later in the day she started to remove the husks.  When she removed the husk from the last ear of corn she had a surprise which she initially thought was a huge insect and she quickly threw the ear of corn into the sink.  When the object didn't budge, she decided to live dangerously and pressed it with her finger to see if it would move.  No, it didn't move. Upon closer examination, it looked a little like mold in certain spots.  So she decided to do what all good "Crop Scouts" do... she Googled it!

Imagine her  surprise when she discovered that corn smut(Ustilago maydis) is a delicacy in Mexico.  A brief perusal of the literature revealed that in some urban markets Huatlicoche sells for $25 per pound.  Chefs in many of the larger cities have incorporated Huatlicoche into their menus. In 1989 the James Beard Foundation held a dinner in its honor, christening it "Mexican truffle" to promote its prestige. It sort of worked. In the '90s the USDA, responding to demand, cleared Florida and Pennsylvania to infect crops with the parasitic fungus. 

Here are some pictures of Ustilago maydis on the ear of corn.

So, the next time you are eating Huatlicoche at that upscale city restaurant remember the fungus that made your gourmet meal possible.

For additional information/articles on Huitlacoche(Ustilago maydis) please visit the links listed below:

1. "Our own" Ray Samulis wrote an article that mentions corn smut (Pest & Plant Advisory dated June 25, 1997):  http://njaes.rutgers.edu/pubs/plantandpestadvisory/1997/vc0625.pdf

2. Here's a link to an article (prepared by W.F. Tracy, C. Vargas, L. Zepeda, J.K. Pataky, and M.A. Chandleron) titled 'Production and Marketing of Huitlacoche' from Purdue:  http://www.hort.purdue.edu/newcrop/ncnu07/pdfs/tracy233-236.pdf

3. Here's another link to an article by Mary Ann Hansen, Extension Plant Pathologist, Department of Plant Pathology, Physiology and Weed Science, Virginia TechVirginia Cooperative Extension:  http://pubs.ext.vt.edu/450/450-706/450-706.html

4. And from the Boston Globe Food Section, an article titled 'His crop isn't pretty, but it tastes great', by Eric Goldscheider, Globe Correspondent:  http://www.eric-goldscheider.com/id103.html

5. An article titled 'Huitlacoche Corn Smut: How to Grow it and How to Prevent It':  http://voices.yahoo.com/huitlacoche-corn-smut-grow-prevent-7588792.html?cat=6

And, if you were wondering about the nutritional value of Huitlacoche...
http://www.examiner.com/article/huitlacoche-eat-your-smut-dear-it-s-good-for-you
http://www.huffingtonpost.com/2010/04/27/huitlacoche-corn-smut-goo_n_553422.html

Other articles/info that may be of interest: 
http://www.news.wisc.edu/12896
http://www.huffingtonpost.com/flora-lazar/corn-porn-learning-to-lov_b_125964.html

Goosegrass and Crabgrass Identification

Goosegrass (Eleusine indica), also called wiregrass, is an annual summer grass and occasionally, a perennial. Goosegrass is normally found in compacted areas or areas of heavy wear; it inhabits agricultural land and other disturbed places, especially those that receive some summer water, and grows close to the ground. Goosegrass is characterized by fibrous roots and very flattened sheaths which have a silvery-green color, especially near the center of the plant. It has finger-like seedheads bearing seeds with a zipper-like appearance on the seed stalk.  It is a widespread and highly variable species that tolerates a broad range of environmental conditions, but does not survive frost.

Crabgrasses are summer annual grasses that generally grow in patches. They inhabit agricultural land and other disturbed sites. Large crabgrass, Digitaria sanguinalis, is more often found in gardens or landscape areas and smooth crabgrass, Digitaria ischaemum, is more often found in turf. Flowering and subsequent seed set take place from mid-summer to early frost and are the means of perpetuating the species. Seed can be produced at mowing heights as low as ¼ inch. Abundant quantities of seed are produced. They vary in number depending on the general health and vigor of the plants.

Courtesy of PennState College of Agricultural Sciences

For color photographs of the life cycle of crabgrass and goosegrass, please use the link below and visit the University of California at Davis IPM site.

UC Davis IPM - Weed Gallery

Crabgrass Control

This week at the Burlington County Community Agricultural Center we noticed the seed heads  of  crabgrass and wanted to remind everyone that late summer and early fall is the best time for establishing a healthy lawn and a weed control program.  The establishment of a healthy lawn is the best way to control crabgrass and other annual weeds.

Some tips for creating a healthy lawn are:

• Test your soil.  Soil Fertility testing should be performed every 2 to 3 years. Apply phosphorus, potassium, or lime based on recommendations of the soil test report.  
• Plant high quality seed of recommended cultivars. 
• Seed in late summer for new lawns. Crabgrass and other annual grasses that germinate in late summer will be killed by frosts in October or November.
• Mow your lawn to a height of 2 to 3 inches. The taller grass shades the soil and keeps soil cool. Crabgrass seeds do not germinate under cool conditions. Adjust your cutting height as appropriate for the turfgrass species in your lawn. 
• Leaving clippings recycles nutrients, sustains soilfertility, and provides for a healthy, vigorous turf that is more competitive against weeds.
• Water heavily once a week and avoid frequent light irrigation.
• Avoid summer fertilization. Crabgrass benefits more from fertilizer application under high temperatures than Kentucky bluegrass and other cool season grasses. 

For additional information on crabgrass and weed control please click on the link below:

Weed Control in Home Lawns

What is Integrated Pest Management?

What is Integrated Pest Management (IPM)?  IPM is a comprehensive approach to solving pest problems.

1. Identify the pest(s) that are the source of the problem. 

2. Understand the biology and economics of the pest and the system in which the pest exists.

3. Monitor pests and natural controls. Use standardized, tested monitoring methods rather than basing decisions on haphazard observation.

4. Establish economic or aesthetic injury thresholds. Pest management decisions are based on the potential damage from pest infestations, status of natural enemies, sensitivity of the protected site (such as stage of development of a crop), and the weather. Actions are taken only when the potential damage is sufficient to justify action.

5. Select an appropriate strategy of cultural, mechanical, biological, and/or chemical prevention or control techniques.

6. Evaluate the pest management program and improve it when possible.