Entomologist, ecologist and plant protection expert Buyung Hadi joined FAO as agricultural officer in charge of Integrated Pest Management (IPM) a year and a half ago. He says the concept of IPM has evolved throughout humanity’s long battle against bugs that feed on crops.

HB: When we first began to intensify crop production, the philosophy was "the only good bugs are the dead ones". The advent of chemical pesticides in the 1940s was like a dream come true for this school of thought. Indeed, some of the first-generation chemical pesticides were highly toxic and they persisted a long time in the environment. 

"Not all bugs are bad": the birth of IPM

A decade or so into this way of managing pests, entomologists started to notice that if five years ago one spray per season was enough, suddenly you needed two sprays, and then you needed three sprays. More and more pesticides became necessary as pests gained resistance to the chemicals.

Then there is the phenomenon of resurgence, in which you spray a pest, and within three weeks it comes back stronger. This is because pesticides typically only kill adult insects. If there are any eggs out there they don't die. When those eggs hatch the insects come back: they find an enemy-free space, and their numbers explode.

People started to do research on this and they realized that "not all insects out there are bad, and when we spray pesticides, we kill the good as well as the bad." A number of scientists in the US started seeing this and thinking, "we need to rein in the use of pesticides and only use them as a last resort." This was the impetus for IPM.

IPM is "like a pyramid"

So then the big question was, what would be the first lines of defence before we turn to pesticides? One way is to use resistant varieties — plants with the ability to kill insects naturally, or an ability to outgrow the bugs and to produce really well in spite of infestations.

We began putting together these building blocks made out of lines of defence. I like to think of it as a pyramid: the base is made up of tactics that are non-toxic, like using resistant varieties, agro-ecology, adding certain organic matter to the soil, planting trees on farms, increasing crop diversity. Then we reach bio-pesticides, which are made from natural ingredients like plants and microbes. And then you have the synthetic pesticides at the top. 

A pyramid has a broad base and can only stand one way. Which means if synthetic pesticides are your starting point, your pyramid crumbles. This is why we must rethink priorities: start at the base, and only work up to the top as needed.

In the end what we want is a method of growing plants that doesn't put people and the planet in harm's way. This is where IPM can contribute, because if you think about it, there are only a few things in the way we grow plants that are harming people and the planet. And overusing pesticides is probably the foremost.

COVID "put a wrench" in the alternatives

COVID has limited everything in agriculture — including the availability of bio-pesticides and biological control agents, because their production and use is very labor- and knowledge-intensive. It involves living organisms, and it takes a lot of human-hours to tend, harvest, process and apply them — it's almost like you're tending a zoo.  

Take maize, for example. This is a staple food crop in countries around the world. It attracts a number of pests, and one of their natural enemies is Trichogramma chilonis, a micro wasp that lays its eggs inside the pest eggs and destroys them from within. It takes up to two releases of 100 000–150 000 of these micro wasps per week for several weeks to successfully control pests on one hectare of maize. 

So COVID may have put a wrench in the production and distribution of biological alternatives. The concern is that in the long run this may lower supplies and drive prices up. We haven't looked at the data yet, but these are the potential problems.

The tide is slowly turning

There are reasons to be optimistic, though. There's a lot more talk about biodiversity and a lot more political will to push for biological, nature-based solutions across the board, not just in agriculture. 

For example, you have the European Green Deal and its Farm to Fork strategy. As well, countries such as Sri Lanka and Bhutan are making strategic policy changes that limit the use of synthetic pesticides and fertilizers in farming. This could lead to the more widespread use of nature-based solutions in pest management. 

You also see this on the consumer side: for example, 20-25% of farmland in Asia is rice fields. So if you want to make a difference in how agriculture is done in Asia, rice is a key pathway. 

In the past it was difficult to find consumers willing to pay extra for sustainably produced rice, but that is no longer the case. Today there is a sustainability standard for production that is supplying eco-friendly rice to the market. And that's how you make change happen. 

In terms of technologies and know-how, we've had them all along. We just need the right market and policy environment for change to occur and the technologies to be scaled up. I'm hopeful that in the next decade we'll be seeing biological solutions in pest management take off. When the political will is there, the rest follows.