When insects attack plants, some plants can summon help from tiny soil microbes. Cowpea plants release chemicals that feed a group of helpful bacteria. These bacteria then make the plant send out a special signal into the air. This signal attracts parasitoid wasps, which hunt and kill the insect pests.
Scientists are studying how long this protection lasts and if other plants use it too. If we can understand this, maybe we can use these wasps to naturally control pests in farming.
The American serpentine leafminer is a harmful insect that attacks crops like cowpeas and beans. Without control, these insects can eat all the leaves. One way to fight them is by using parasitoid wasps. The wasps lay eggs inside the leafminers. When the eggs hatch, the young wasps eat the pests.
Plants already use chemicals to attract wasps to their leaves when they’re being eaten. But these signals don’t last long. However, plants can also shape the bacteria in the soil around their roots. Insect attacks change what kinds of microbes are there. This new study shows how plants might create a lasting defense system using these underground allies.