Why engineering plants increase the agricultural waste?

I read the fifth paragraph of an article as below:
Quoted Unfortunately, an alternate pest-fighting strategy that also uses genetic modification—engineering plants to be resistant to pesticides and herbicides—has the opposite effect, generally leading to an increase in agricultural waste. Unquoted
I do not understand (1) Why engineering plants would increase the agricultural waste? (2) The engineering plants would create what kind of agricultural waste? Thank you very much!

The whole article is as below for your reference:

Earth Talk: What’s the latest on genetically engineered products’ health impact?
• by E/The Environmental Magazine /© 2020, Emagazine.com.
Distributed by Tribune Content Agency, LLC.

Few topics are as divisive as genetic engineering. Plants and animals that have had their genomes artificially altered now dominate the world of agriculture. In grocery stores, over 60% of processed foods contain at least some components derived from GMOs. Given all this, it makes sense to ask whether or not these altered forms of life have deleterious effects on humans or the environment. When it comes to human health, the evidence suggests GMOs are harmless. Exhaustive meta-analyses of scientific studies on GMOs have generally found no links between their consumption and negative health outcomes. However, there are some caveats. One is that the biotechnology companies responsible for the creation of GMOs have also been
responsible for a large portion of the research on their health effects. Therefore, financial conflicts of interest may have tainted the research. Additionally, many scientists feel that the jury is still out on the safety of GMOs. A 2015 scientific
paper, signed by 300 independent researchers, states that the effects of GMOs on health remain “unclear.”

Another factor is that scientific studies on GMO-related health risks have generally been short term. It could still be that GMOs are causing health issues, but we’ve failed to establish a causal link because of how long these issues take to manifest.

Environmental impact

Environmentally, GMOs are a mixed bag. Most crops are genetically modified to fight pests. There are two ways to accomplish this goal. The first is to create plants that produce pest-killing toxins. These types of GMOs can actually be good for the environment in that they often don’t require as many pesticides as unmodified plants.

Unfortunately, an alternate pest-fighting strategy that also uses genetic modification—engineering plants to be resistant to pesticides and herbicides—has the opposite effect, generally leading to an increase in agricultural waste.

Shrouded in uncertainty

GMOS seem to have some benefits, and many scientists believe they can help address world hunger. However, there’s still a chance GMOs could cause health issues, and they have already caused some environmental issues.