Multi-dimensional combat: climate change makes pests more resistant to pesticides

Multi-dimensional combat: climate change makes pests more resistant to pesticides

Multi-Dimensional Strike: Climate Change Increases Pest Resistance Multi-Dimensional Strike: Climate Change Increases Pest Resistance

Picture of Plutella xylostella infestation Picture courtesy of Institute of Plant Protection, Chinese Academy of Agricultural Sciences

Picture of Plutella xylostella infestation Picture courtesy of Institute of Plant Protection, Chinese Academy of Agricultural Sciences

What? Climate change and insect resistance are closely related!

On September 9th, the latest paper published online by "Nature-Communication" found for the first time that climate change can promote the development of pest resistance by expanding the overwintering range of pests
.

"Climate changes caused by human activities such as greenhouse gas emissions have threatened global food security, and the extensive use of pesticides has also brought risks to human health and the ecological environment
.

" Ma Chunsen, a researcher at the Institute (hereinafter referred to as the Institute of Plant Protection), told the China Science Daily that the climate change revealed by this study will cause the expansion of pest distribution and increase in pesticide resistance, which will cause multi-dimensional blows to agricultural production and increase the difficulty of pest control.

Overwintering and drug resistance: irrelevant or closely related?

Overwintering and drug resistance: irrelevant or closely related?

The pest of interest in this study is Plutella xylostella
.

As one of the most serious agricultural pests in the world, the diamondback moth causes more than 4 billion U.

Image courtesy of the adult diamondback moth, Institute of Plant Protection, Chinese Academy of Agricultural Sciences

Image courtesy of the adult diamondback moth, Institute of Plant Protection, Chinese Academy of Agricultural Sciences

As early as 1988, Ma Chunsen began to study the overwintering problem of Plutella xylostella
.

He conducted field investigations in Gongzhuling, Jilin Province, Wuhan City, Hubei Province, and Henan.

In 2008, Ma Chunsen participated in a research project on pesticide resistance monitoring and management of Plutella xylostella
.

During the project research, he discovered that the diamondback moth resistance problem is very serious in the south of the Yangtze River in China, while in the northern areas where the diamondback moth cannot survive the winter, almost no problem has been heard of drug resistance

Ma Chunsen quickly realized: “Plutella xylostella resistance may be related to its survival
during the winter.

I am very concerned about the overwintering problem of the diamondback moth.

However, at that time, the issue of pest distribution and resistance was usually studied independently, and it was not clear whether the two were related
.

Zhang Wei, the co-corresponding author of the paper and an associate researcher of the Institute of Plant Protection, told China Science Daily that although it was realized that overwintering may be beneficial to the evolution of drug resistance, the development of drug resistance is affected by other factors.
Close relationship
.

For example, the number of generations of the diamondback moth is different in different regions, and the number of generations is more resistant.
The development of resistance is fast; the difference in lethal mechanisms and cross-resistance of different pesticide types will affect the development of resistance; different regions and even different fields have different man-made drug habits.
Drug resistance will also be different
.

"These factors are mixed together, so that we can not isolate the relationship between winter survival and drug resistance
.

" Zhang Wei said that the research team further in-depth research, conducted a global big data analysis of diamondback moth resistance, and also considered the above interference factors

 

The key to survival through winter: chronic lethal effects under low temperature

The key to survival through winter: chronic lethal effects under low temperature

"As expected, there is a close relationship between overwintering and drug resistance
.

" Ma Chunsen said

In order to determine what climatic factors determine the survival of the diamondback moth in winter, they designed an indoor simulation experiment
.

The artificial climate box was used to simulate the winter temperature changes in 10 locations at different latitudes in China, and the survival rate of the diamondback moth larvae and pupae under different winter conditions was tested

In order to test the overwintering survival model obtained by the laboratory and predict the overwintering survival ability of the diamondback moth in the complex and changeable field environment, they were in Shenyang, Beijing, Hebei Shijiazhuang, Shanxi Datong and Taiyuan, Shandong Huimin, Henan during 2008-2013.
Field trials of diamondback moths were conducted in 12 locations including Anyang, Zhengzhou, Zhumadian, Wuhan, Hubei, Changsha, Hunan, and Guangzhou, Guangdong
.
Considering that Plutella xylostella may overwinter under the stubble leaves of the harvested plant, they also designed two overwintering environments on the plant and under the stubble leaves to test the survival rate of the diamondback moth larvae, pupae, and adults under different winter conditions.

.

Ma Chunsen said that with the aid of the above experiments, they analyzed the key climate factor that restricts Plutella xylostella overwintering, namely low-temperature accumulated temperature (the accumulated temperature below 11°C in winter), and constructed a low-temperature daily model
.

When the winter temperature is lower than 11°C, some diamondback moths begin to die
.
In very cold areas in northern China, such as the Northeast, the lowest temperature is lower than the extreme low temperature that the diamondback moth can tolerate (the supercooling point is -13.
5°C~-20.
1°C), and the diamondback moth must not overwinter
.
In the vast North China Plain and other places, the temperature in winter is often higher than the supercooling point, and the diamondback moth cannot survive the winter
.

In other words, the diamondback moth did not freeze to death in these areas, but died of cold for a long time at a temperature that was not too low
.
"This chronic lethal effect is the key to determining the winter survival rate
.
" Ma Chunsen said
.

To this end, they constructed a wintering survival model of Plutella xylostella based on low temperature and accumulated temperature in winter, and calculated the overwintering survival rate of Plutella xylostella in different regions and different years
.

The optimal model for the wintering survival of the diamondback moth and field validation

The optimal model for the wintering survival of the diamondback moth and field validation

In the complex natural climate environment, this model can explain the survival rate of 62.
1%, far exceeding the previous low-temperature survival models
.
"Such high accuracy is mainly because the model accurately simulates the low temperature death process of the diamondback moth, that is, long-term low temperature damage, rather than frostbite at extremely low temperatures
.
" Zhang Wei said
.

"The climate factor of low temperature accumulated temperature and day is easily obtained from past climate data and future scenarios
.
" The author of the paper and professor at Rice University (Rice University) Volker Rudolf said that it can be calculated with only the average daily temperature
.
The daily average temperature values ​​of the world and China are easily available in major public climate resource databases
.

"Because of its easy availability, we have been able to study the survival of diamondback moths worldwide and the trend of drug resistance changes under climate change,
" Rudolf said
.

 

Overwintering area and non-overwintering area: 158 times difference in drug resistance

Overwintering area and non-overwintering area: 158 times difference in drug resistance

They found that in the past 50 years, climate change has expanded the global wintering area of ​​Plutella xylostella by 2.
4 million square kilometers; every 1°C increase in the average temperature in the future will cause the wintering area to expand by 2.
2 million square kilometers
.

Ma Chunsen said: "The findings of the research on the overwintering of the diamondback moth, coupled with the analysis of big data on the resistance of the diamondback moth in the world over 40 years, reveal how climate change affects the distribution of resistance of the diamondback moth in the world
.
"

Based on the winter low temperature accumulated temperature model of the diamondback moth overwintering, they divided the diamondback moth's global occurrence areas into overwintering areas (winter survival <1%), sporadic overwintering areas (1~5%), and non-overwintering areas (winter survival ≥5 %)
.
China's Henan Province is the "marginal" zone where the diamondback moth overwinters
.
It is worth noting that the resistance of Plutella xylostella in overwintering areas is 158 times that of non-overwintering areas
.

The distribution of diamondback moth resistance in wintering areas, sporadic wintering areas and non-wintering areas in China and the world

The distribution of diamondback moth resistance in wintering areas, sporadic wintering areas and non-wintering areas in China and the world

Ma Chunsen explained: “In non-wintering areas, winter populations either die or move to warmer areas
.
The spring population in the second year is a mixed population.
These individuals move in from multiple areas where different types of pesticides are used.
Therefore, local drug resistance cannot accumulate and evolve across seasons
.
On the contrary, populations in overwintering areas occur throughout the year and can quickly accumulate resistance genes
.
"

The study pointed out that pest management strategies should be adjusted during the production process to adapt to differences in pest survival in different regions
.
In perennial overwintering areas, it is recommended to use green prevention and control technologies, or use chemical pesticide substitution technologies, and alternately use pesticides with different action mechanisms for treatment; while in non-overwintering areas, use pesticides with different action mechanisms as far as possible from the overwintering areas to facilitate Slow down the development of drug resistance
.

Like the diamondback moth, many important agricultural pests, including armyworms, planthoppers, leaf rollers and aphids, occur throughout the year in warm southern regions, and migrate north to non-overwintering areas in spring
.
These pests occur in many generations, and the amount of pesticides used for prevention and control is large, and the resistance to pesticides is serious
.

"Although they have not studied the relationship between their overwintering and drug resistance, it is speculated that they have similar results with the diamondback moth
.
" Ma Chunsen said that China is a large vegetable producer.
This research not only fills the knowledge gap of the diamondback moth overwintering, but also contributes to climate change.
The study of survival and overwintering distribution in the next winter will provide a model
.
More importantly, the study provided for the first time evidence that climate change promotes increased pest resistance, and it was confirmed that it was driven by the expansion of the overwintering range
.
(Source: China Science News Li Chen)

Related paper information: https://doi.
org/10.
1038/s41467-021-25505-7

https://doi.
org/10.
1038/s41467-021-25505-7