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Aug 18, 2018 27 tweets 7 min read Twitter logo Read on Twitter
With Glyphosate being in the news due to a recent court ruling, let's take this opportunity to explore the history of pest control in this week's #DeepDive.

It's a huge and complex topic, so the best we can do is a brief overview.
It's not really known when humans started using pesticides.

The first agricultural societies began about 10,000 BCE, with several independent shifts around the world from relatively nomadic lifestyles to those tending crops.
The first records of pesticides being used is in Sumeria, where they used elemental sulfur to control crop pests.

This is largely an accident of geography; Sulfur deposits are abundant in a stretch between Mosul and Fatha...which allowed easy access.
Over in China, one plant used historically for pesticide use was the Chinaberry tree...which we know contains a lot of different toxins. It was mainly used for household pests, although there was some use in agriculture.
In India, the Neem tree was also used quite a bit in traditional medicine...and a few thousand years later, it was found that Azadirachtin was the active ingredient.
So, the earliest attempts at pest control that we're aware of all revolved around using what was found in the area that seemed to kill bugs well.

These were either natural minerals or plants which had been used in medicine.

Sometimes these worked, sometimes they didn't.
As agriculture grew, farmers became more inventive...although exact dates are hard to come by.

Later developments included the use of ash as a repellent/suffocant, sulfur fumigation, and use of oil to keep insects from laying eggs.
One of the most sophisticated pest control techniques of the ancient world wasn't chemical-it was biological!

Around 300 BCE, the Chinese were using weaver ants to control caterpillars and beetles which attacked Citrus crops!

In ancient Rome, we see this pattern continue. Many authors (including Aristotle) valued aromatic plants for their pest control qualities, and Pliny the Elder even recommended what appears to be an attempt at vinegar fumigation.
About 800 BCE, we start seeing sophisticated storage methods.

Grain was often kept in huge pits, and people started developing techniques to reduce moisture and oxygen to prevent insect and fungal growth.

So even back then, we were on top of things.
Another thing folks figured out about this time was that you could separate out insect pests from the seeds by letting the infested grains float up.

This method is still used by some cultures today, although methods are more complex.

From here on out, it's a bit of a grey area. We know that pest control developed, and there's even some discussion of arsenic compounds being used in the middle ages...but there's not a lot of information I could find.
So...a lot of pest control techniques were developed very early, and pest control looked the same until the late 1800s.

During the 1700s and the 1800s, there was a rapid change in agriculture from a subsistence lifestyle to a more commercial business enterprise.
At the same time, the game was changing. We had taken a lot of crops out of their home ranges, and pests had adapted to feed on them.

In essence, we accidentally domesticated *a lot* of bugs.…
Around this time, we see the development of a lot of insecticides using arsenic. We'd known that arsenic containing dyes-usually green ones-were toxic to people, so we started using them to combat insects.
Around this time, we also started to develop the tools to make spraying for pests easier.

If you're familiar with old-timey cartoons, you may recognize this. This is one of the first widely available pesticide sprayers which were used on farms.
After this, we start to see a rapid development of pesticides...and the period of 1920-1970 should really have it's own thread.

DDT was the biggest leap in this era, and it's super important because it was practically non-toxic.…
However, there was some environmental damage which occurred because of widespread applications. Rachel Carson discussed this very widely in Silent Spring.…
Again, this needs its own thread to properly discuss, but Silent Spring was another turning point for pest control.

Yes, Carson got some stuff wrong. Yes, banning DDT was somewhat political.

DDT use was already declining due to increased pest resistance.…

This also popularized the idea of 'least use' approaches to pest management, and the idea that we should treat only when farmers will lose revenue due to losses by pests.
As time goes on, we see techniques get ever more sophisticated.

Starting in the 1910s, we start seeing the development of Bacillus thuringiensis as a pest control product. China and Brazil start developing viral pesticides.
In the 1990s, for the first time, we start seeing transgenic crops...and this brings yet another new era.

It's recognized that these crops can be fairly specific, and we can find and use highly specific proteins.

We also start caring about management of resistance to pcides.
See, by now, we've been watching all sorts of bugs get resistant to insecticides. So much so that one species-the Colorado Potato Beetle-has become a symbol of political resistance.

...and that's where pest control's going in the future.

Resistance is a big issue, and techniques are being developed to combat it.

Development may be slowing down. This is somewhat in part to regulation, but also because companies want to make less toxic pesticides.

So they're a bit more choosy nowadays.
Between 1995 and 2014, the number of compounds companies went through to find a successful product nearly tripled from about 50,000 (1995) to 150,000 (2014).

In addition, costs also increased greatly.

Automation, and enhanced high-throughput screening techniques will help.
If you're curious about the economics of the industry, the below is a great place to start.

So...pest control has changed a lot over the years.

It's gone from using local plants and minerals, to a process which screens hundreds of thousands of compounds to find a single product.

It's also going to change in the future, especially with the advent of robotics and AI.

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More from @BugQuestions

Aug 26, 2018
Yeah, we get pictures/videos of this occasionally.

Ants don't really do 'funerals'; even the dead in their own colonies are put into a garbage dump rather unceremoniously.

There's a handful of possibilities for this behavior...
1.) They may be attempting to bury it, especially if it's on a hard surface.

Lots of ants bury large food items to protect it from scavengers, other ants, and to absorb liquid which comes out from the prey.
2.) The critter happened to fall into the colony's trash pile.

Ants put waste (dead ants, poop, shedskins, etc) into a large pile called a 'midden pile' which functions just like our landfills.

If something ended up in that pile, they could be moving stuff out of the way.
Read 4 tweets
Aug 25, 2018
I think this problem hits at the heart of the issue when it comes to Eckbom's, because it's often not about infestations.

This deserves it's own thread to describe how complicated this problem is, and how poorly understood it is.
So...first, I believe that these people are accurately describing their perceptions of medical issues.

Urban IPM Extension people can go through samples to find insects, inspect homes for infestations (bed bugs, fleas, etc), get someone to do skin scrapings for Scabies, etc.
However, after that, they need to be passed onto a doctor.

Often times, attempts at self-treatment can cause skin irritation. Pesticide poisoning can also cause crawling sensations.

Brain tumors, autoimmune diseases, even cold weather can do this as well.
Read 4 tweets
Aug 25, 2018
Scientists make their living using their brains to interpret data.

So what happens when that organ breaks, and a respected researcher becomes mentally ill?

In this week's second #DeepDive, let's explore the case of Jay Traver.

CW: Mental illness
Jay Traver was one of the early entomological pioneers. Her career centered mainly around aquatic insects, specifically mayflies.

Most of her work-which is still cited to this day-revolved around describing the lifecycles of mayflies.
In 1951, Traver published a paper where she claimed to have experienced an infestation by a mite called Dermatophagoides scheremetewskyi.

This is a mite which lives in homes, and although it causes allergic reactions, it was known at the time to not be parasitic.
Read 15 tweets
Aug 24, 2018
A new meme going around FB claims the WoodLouse Spider is a "deadly new species" wrecking havoc in the Southern US

It's a completely harmless spider, but it still has a neat story to tell.

For the first of this week's two #DeepDives, let's explore the biology of Dysdera crocata
So, for the first tweet in this series, let's put these rumors to rest with data.

There's a lot of verified bites from D. crocata in the medical literature-which is rare. One person allowed themselves to be purposely bitten multiple times.

No deaths; everyone was just fine.
D. crocata gets it's name-the woodlouse spider-from it's food.

They live in dark, moist, areas and are adapted to feeding on sow bugs...sometimes called rollie-pollies.

They use those huge mandibles to foil the isopod's defensive rolling.

Read 8 tweets
Aug 21, 2018
It is with a heavy heart that we announce that one of our colleagues, Vazrick Nazari, has been arrested for possession of child pornography.

We cannot tolerate exposing our followers to this sort of person, and have blocked him from our feed.…
We did consult him for help with moth IDs here on Twitter, and although there's no way we could have known he was doing this, we still feel the need to apologize for exposing our readers to-and let's just put it as bluntly as possible-an alleged child predator.
We try to be careful about who we consult, and let into our conversations.

Unfortunately, it's not always possible to know what's going on behind the scenes.

Needless to say, we will not be requesting any more assistance from this person.
Read 4 tweets
Aug 12, 2018
For tonight's #DeepDive, let's talk a little bit about how insects use venom *and* poison for various things.

The divisions can be weird, and there's a lot of ways that venoms and poisons can be used!

Thanks to @RosemaryMosco for comic permission!…
When we think of venom or poison, we typically think about the act of eating...and for good reason.

Venom/poisons are used to either help something eat, or keep something from being eaten.
The only exception to this that I'm aware of is the mating of the African rock scorpion.

During mating (2:10 in this video), the male stings the female.

This species doesn't use venom to hunt, so the exact reason behind this behavior is unknown.

Read 17 tweets

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