Tarantulas and soil bacteria: improving agricultural technology

One of the cool things about agricultural technology is that it gets both more effective and safer over time.

Agricultural chemical manufacturers are developing products that have much shorter lives—that break down far more quickly and don’t persist in the environment nearly as long as earlier products. 

“Contrary to the one-dimensional view of pesticides as broad-spectrum and persistent, recently developed insecticides are highly selective for insect pests,” write the authors of a report on potential pesticides.

I chatted with a South Illinois corn and soy farmer last week. His 1,500-acre family farm has virtually stopped using insecticides—which were extensively used a generation ago.

He said the use of insect-killing chemicals on his farm has been made unnecessary by stacked traits that put varieties of the Bacillus thuringiensis into the seed—so the plant itself prevents insect attack and chemical sprays are unnecessary.

It has the additional benefit of impacting only those insects actually feeding on the crop. Other insects in the environment are not impacted.

He still uses herbicide, but generally in just two applications annually. His farm has gone to no-till agriculture, and he applies glyphosate herbicide once to kill off the spring growth, and most years one second application later in the year is all that is necessary. Sometimes the second application is avoided.

He said that when he started farming half a century ago, the chemicals were heavily used and were dramatically toxic or caustic. His overall use of chemical additives is down dramatically, and his soil is healthier than it was, he said.

This farmer said he’s a believer in technology. It made his farm profitable, and something his two adult sons are interested in taking over.

One of the interesting features about some new insecticides is that they’re patterned after natural products. Bacillus thuringiensis is a natural soil-born bacterium. By inserting the effective sections of Bt’s genome into agricultural plants, the plants are provided with the ability to protect themselves.

Some researchers are now looking at another natural product, tarantula venom, as a potential agent for pesticides. 

Here is the original paper on that.  Here is the Science Daily report on the research. 

It turns out tarantula venom isn’t only scary to humans, but very effective against the cotton bollworm and other insects. And they don’t have to be stung; they can be killed from eating it.

There are cautions here, though. since some of these biopesticides or “botanicals” may actually be more toxic in the environment than their synthetic cousins.

“Synthetic pesticide use has been the dominant form of pest control since the 1940s. However, biopesticides are emerging as sustainable pest control alternatives, with prevailing use in organic agricultural production systems,” write the authors of the paper, “Bioinsecticide-Predator Interactions: Azadirachtin Behavioral and Reproductive Impairment of the Coconut Mite Predator Neoseiulus baraki.” 

They warn that while natural and approved for organic farming, azadirachtin has certain toxicity issues. The authors note that 70 percent of synthetic insecticides have natural analogs, but that the natural ones are not always safer.

Azadirachtin, which is approved for organic farming, is derived from the seeds of the neem tree. One concern is that its use as an insecticide can screw up the natural relationship between problem insects and their natural predators—since the predators are also impacted by the insecticide.

The used of the product “may lead the predators to leave the area, compromising the biological control,” and ultimately making farmers more reliant on chemicals.”

Clearly, this stuff is complicated, but it’s heartening that as more study occurs, we’re understanding relationships better and developing better agricultural controls.

© Jan TenBruggencate 2015

Fact Check: Agricultural pesticide use peaked 30 years ago

There’s been lots of discussion, assertion, and misinformation in the Hawai`i GMO battles in recent years about what’s been happening with U.S. agricultural pesticide use. 

That's amid critical assertions of "more and more" pesticide use, and hyperbolic claims that tons and tons of pesticides are being dumped on the land. The real story is more nuanced.
 

The U.S. Department of Agriculture last year did a thorough review of the subject, in a report called “Pesticide Use in U.S. Agriculture: 21 Selected Crops, 1960-2008.”

 

“The examination of pesticide use trends is critical for informed pesticide policy debate and science-based decisions,” the report says.

Some key points from the study:

• Pesticide use in American agriculture peaked more than 30 years ago, and on average has been dropping since.
• Agriculture is using a lot more weed killer than it used to, and far less insecticide.
• It is using chemicals that are far safer and yet more effective than before.
• Corn farming gets hit with being a big pesticide user, but that is partly because there are a lot of acres in corn. The crop uses pesticides more sparingly than cotton, fruit and vegetable farming.

Pesticide use in U.S. agriculture grew rapidly through the 1960s and 1970s, peaking in 1981 at 632 million pounds of active ingredient. (See our note on the whole active ingredient thing at the bottom of this article.)

And pestide use has been going down since then, to 516 million pounds in 2008, the most recent year with complete numbers.That’s a 19 percent drop in pesticide use. The drop in total acreage in U.S. agriculture during the last 30 years was about 9 percent. 

If you're thinking that agricultural use of pesticides is dominant, think again. It represents less than half of all U.S. pesticide sales, which according to the EPA exceed 1.1 billion pounds annually. If you include wood preservatives, specialty biocides, and chlorine/hypochlorites, the amount climbs to more than 5 billion pounds.

While the overall amount of active ingredient in agricultural pesticides has been slowly decreasing, the relative use in different classes of pesticides has changed dramatically. There has been a wild drop in the amount of insecticide, but a big increase in the amount of herbicide. 

“As a result of increased adoption of Bt corn by U.S. farmers for insect control, insecticide use declined steadily from 0.24 pound per planted acre in 1996 to 0.15 pound by 2000 and 0.05 pound in 2008. Insecticides accounted for only 2 percent of total pesticide pounds applied to corn in 2008,” the report says (USDA report page 65.)

That change is a key reason overall use has dropped. Insecticides used to be the largest category of pesticides in agriculture.

“Insecticides accounted for 58 percent of pounds applied in 1960, but only 6 percent in 2008. On the other hand, herbicides accounted for 18 percent of the pounds applied in 1960 but 76 percent by 2008,” the report says.

Fungicides stayed relatively even at 7 percent, and “Other pesticides—which include soil fumigants, desiccants, harvest aids, and plant growth regulators—generally accounted for 5-11 percent of total pesticide use from 1960 to 1992, increased to 17 percent of use in 2002, and then declined to 13 percent in 2008.”

It is also clear that the individual pesticides have changed, since “the EPA determined that some pesticides, such as DDT, aldrin, dieldrin, chlordane, and heptachlor, posed unreasonable risks and their registrations were subsequently canceled.”

Which crop uses the most total pesticides? Corn used 39 percent in 2008. Soy used 22 percent. Potatoes 10 percent. Cotton 7 percent. And wheat less than 5 percent.

Those are totals and not per-acre numbers. The ranking  roughly correlates with acreage. The EPA reports that, as of 2011, the largest crop by acreage was corn (84 million acres), followed by soy (73.8), hay (55.7) , wheat (45.7), cotton (9.5), sorghum (3.9)  and rice (2.6.)

The National Potato Council reports that potatoes cover less than those crops—about 1 million acres. Pesticides are also used on dozens of other crops. Apples, oranges, peanuts, sugar cane, tomatoes, grapes and many others. 

“Corn producers apply more pounds of pesticide than any other crop farmers, but use pesticides much less intensively than cotton, fruit, and vegetable producers. For example, potato producers use about 50 pounds per planted acre, versus 2.4 pounds per corn acre,” the report says (Page 62.) 

The uses are also different. Corn uses herbicides more, and potatoes use more fungicides than herbicides or insecticides.

Is research improving the levels of safety? The report argues that it is. The most hazardous compounds have been banned. New formulations have allowed the reduction in usage from pounds per acre to ounces or fractions of an ounce. Many newer insecticides are used at far lower rates than previous chemistries, the report says.

And the EPA has ramped up its requirements for toxicity and human health risk studies.

But what about the dramatic rise in herbicides while insecticides, fungicides and other agriculture chemical remain comparatively low? The report says it is largely a price-driven phenomenon.

“As several new effective products were introduced, the cost of pesticides fell relative to other pest control practices over the period and encouraged substitution of pesticides (particularly herbicides) for labor, fuel, and machinery use in pest control,” the USDA report says.

That means farming got cheaper as a result. In the mid-1960s, energy costs, wages and pesticide costs were about equal in terms of their cost to farmers. Today, pesticide costs are by far the lowest of those three for American farmers. (see USDA report Page 17.)

(Let’s make a side point here that in this report, the USDA actually calculates pesticide quantities in terms of amount of active ingredient. 

(In the same way that a cup of pure sugar is different from a cup of water with one teaspoon of sugar mixed in, a container of weed killer with 40% active ingredient is different from 2% active ingredient. 

(When someone talks about “tons of pesticides” without distinguishing active ingredient, it’s not particularly useful information. Could be tons of water, with a few ounces of active ingredient.  

Could be something else.)

© Jan TenBruggencate 2015

Hurricanes this year a near slam dunk: Be ready

NOAA’s Central Pacific Hurricane Center is predicting an El Nino this summer, and that means a much higher chance of hurricanes in our part of the Pacific.

And we’re due. More on that later.

(Image: This is a satellite image of the eastern Pacific from today, May 27. The storm system with the red X shows strong signs of developing into a more powerful storm. Credit: NOAA.)

This year, the NOAA numbers make hurricanes a statistical slam dunk. Nearly 20-1 odds that we’ll see big storms before December.

That’s not a guarantee, but the odds are looking spookier for hurricanes than they have in a very long time. 

The part of NOAA’s package of statistics that is most concerning is not so much that we are likely to have a more active hurricane season. They predict that in any El Nino year.

What’s concerning this year is that there’s only a 5 percent chance of a less-than active hurricane season. And a 95 percent chance of a normal to higher season. That’s weighted strongly (70% to 25%) in favor of more than normal.

Although the average year sees 4 to 5 tropical depressions, tropical storms and hurricanes in our part of the ocean, there have been years when there have been virtually none. And we’ve been quiet for what seems like a very long time.

The last time the state took a direct hit was Hurricane Iniki in 1992—23 years ago.

Before satellites, it was hard to identify major storms in the Pacific unless a ship ran into one, or it hit an island. But in terms of storms that have caused damage, there were Nina in 1957, Dot in 1959, Iwa in 1982, Estelle in 1986, Iniki in 1992.

That’s five big storms in 35 years, or one every seven years on average.

And the longest time between them was Dot to Iwa, 23 years. Same as the time from Iniki to 2015.

This may be the year to pay attention. Says NOAA:

“This outlook is based upon the expectation of El Niño continuing and possibly strengthening as the hurricane season progresses. 

“El Niño decreases the vertical wind shear over the  tropical central  Pacific, favoring the development of more and stronger tropical cyclones. 

“El Niño also favors more westward tracking storms from the eastern Pacific into the central Pacific.

“This combination typically leads to an above-normal Central Pacific hurricane season.”

The Central Pacific Hurricane Center  is careful to say it can’t guarantee one or more of those storms will actually hit the Islands, but it does encourage families to sign up for emailed weather alerts, to sit down and talk about what they’ll do in the event of a storm, and to put together a hurricane kit. 

If you have a phone book, there are instructions in the front pages. If not find hurricane preparedness tips online.

You can join NOAA’s central Pacific hurricane page on Facebook 

. 

Oh, and while the hurricane season doesn’t start until June 1, there is already a weather system headed this way. See the image above.

It’s still off Mexico, but has an 80 percent chance of developing into a tropical depression in the next two days, and 90 percent in the next five days.

© Jan TenBruggencate 2015

Superweeds and pesticide resistance in Hawai`i

The diamondback moth, a major pest of Hawaiian watercress, cabbages and other crucifers, has repeatedly developed resistance to pesticides used to control it.

There has been a lot of discussion in the Islands about weeds gaining resistance to pesticides used on genetically modified crops, but pesticide resistance has been an issue for farmers since long before genetic modification became prevalent. 

(Image: Diamondback moth larvae feeding on cabbage. Credit: Doug Wilson, USDA.)

Almost every pest control method—organic and synthetic pesticides, and even cultural techniques like crop rotation, have been defeated by persistent pests. 

The message of pesticide resistance is that there’s no magic bullet. Farmers need to use a range of techniques to control their pests—they can’t simply count on a single chemical spray to solve all the problems.

In the case of the diamondback moth, Plutella xylostella, it became resistant to pyrethroid pesticides in Hawai`i in 1992, and when farmers switched to using another natural pesticide product, Bacillus thuringiensis, the bugs began developing resistance to it in three years.

And not just in Hawai`i—the resistance appears everywhere. 

Farmers have switched to other pesticides and have fine tuned their applications to try to defeat it, but are increasingly depending on biological controls—other insects that feed on the various life stages of the moth. Researchers are looking at increasing the effectiveness of viruses that attack the moths, and there's some genetic modification of moths underway in hopes of improving control.

But with respect to pesticide use, there’s still a concern, as consumers insist on food crops that look nice: “In food crops where damage to vegetables must be minimal, chemical control has not been eliminated by biological control,” wrote Ronald F.L. Mau and Jayma L. Martin Kessing of the University of Hawai`i at Mānoa.

How pesticide resistance develops is pretty simple to explain. In every population, there are a few individuals that will be tolerant of a new pesticide—will survive it. The few who survive will be the only ones to reproduce—and their offspring are far more likely to be tolerant. Soon, if you keep using the pesticide, most of the population will be resistant to it and your bug spray will no longer be effective.

Resistance is found for fungicides, insecticides and herbicides as well as for some cultural techniques. There is a bug that responded to farmers switching to a different crop every other year, by going dormant for the intervening year so they’d be ready when the original crop was again available.

But while pests are resilient, so are farmers. There are numerous techniques to overcome pesticide resistance.

“Growers can help delay the development of resistance by applying pesticides only when they are needed, by rotating between different chemical classes, and by using rates of pesticides within the labeled range. Integrating non-chemical approaches such as pheromone mating disruption and cultural controls can also help delay resistance,” wrote the authors of Fruit Crop Ecology and Management, a publication of Michigan State University. 

So, some of the techniques to combat resistance:

Use pesticides that biodegrade rapidly, so subsequent generations of pests aren’t exposed and don’t further increase resistance.

Use combinations of pesticides—some may be resistant to one or the other, but few to both.

Plant “sacrificial” crops—either in nearby fields or even every other row—so there are always non-resistant bugs for resistant bugs to mate with, reducing the overall resistance. Alternatively, leave some areas untreated.

Learn more about the pests and use a tighter target—in the case of a bug, attack only a specific life stage rather than trying to kill the larvae, the adults and the rest all at once.

Experiment with non-pesticide techniques to reduce bug numbers—remove plants they require to complete their life cycle, rotate crops to reduce buildup of crop-specific pests, use baits and attractants to draw pests away from the crops.

And there are other techniques. 

One that doesn’t work well is a homeowner’s solution of simply using more pesticide in hopes of getting ALL the pests.

“Deceptively reasonable on first inspection, this approach rarely works in practice. The reason is that pesticide residues are usually deposited very unevenly in most field situations, even when very high rates are used. Uneven deposition of pesticides allows resistant pests to survive in greater proportions than susceptible pests, thereby increasing resistance,” says Washington State University’s online pamphlet on pesticide resistance. 

The popular press likes to write about Roundup-resistant "superweeds." But they are, of course, not super in any way other than Roundup resistance. They're still susceptible to mulching, to other herbicides, to hoes and mowers, and to techniques that restore their Roundup sensitivity.

Pesticide resistance is not the end of the world—but its management is a significant and normal part of modern farming. 

The Washington State paper says integrated pest management, including moderate, targeted pesticide use, has been shown to work. Key missions for the farmer, Washington State says:

They must monitor pests regularly, carefully manage (not overuse) their treatments, and “make full use of nonpesticidal methods, such as biological and cultural control, sanitation and host plant resistance.”

The whole issue of resistance is complex—stacks of scientific papers and many very dense books have been written about it. Included above are just a few insights into the issue.

Missouri farmer Blake Hurst was quoted in the New York Times:

"The war between man and weed goes on. No different than it has since the beginning of time,"

© Jan TenBruggencate 2015