Figure 1.

The push‐pull for the control of stemborer moth larval damage to cereals on small holder farms in sub‐Saharan Africa is explained in this annotated cartoon, and in the text,5, 9 for the further control of the parasitic weed Striga hermonthica8, 10 and more recently for the fall armyworm.11, 12 This push‐pull intervention against the pests and the agro‐ecological advantages of plant nutrition and other factors13 gives three fold cereal yields with no seasonal inputs of fertilizer or pesticide even under climate change stress.14, 15 The intervention comprises grass and legume perennial companion crops, highly valuable as farm animal forage bringing further value to the small holder farms. The chemistry underpinning these processes is defined and offers possibilities for exploitation by genetic modification of the food crops themselves which work at the field scale providing clear evidence that manipulation of pests and weeds by these plant secondary metabolites can be usefully effective6.