Adding diversity to your cropping system can help naturally control insect herbivores
An increase in plant diversity decreases the need for pesticides. A team of German researchers found that increasing plant biodiversity enhanced natural pest control (Barnes et al. 2020). This could reduce the need for pesticide applications.
In organic operations, making a conscious effort to increase the kinds of plants could result in healthier plants with better yields. For example, instead of planting a field of tomatoes only, add basil or oregano in the rows to attract bees and garlic to help repel pests. In addition to providing a healthy and diverse environment, this plant grouping will also add a little zing to your pasta sauce.
Why diversity works:
- Insects eat less: The original study found that in more diverse grassland communities the feeding rate of insects was 44% less than the feeding rate in a grass monoculture. It is harder for insects to find their preferred plant to snack on in a diverse system. Interestingly, plants in a mixed group contain less nitrogen which makes them less appealing to insects.
- Plants grow better surrounded by a mixed group of friends. Diversity increases the total biomass of an area when compared to a monoculture.
- Predators thrive in a diverse setting. Both the biomass and the feeding rates of predators such as spiders, beetles and wasps increase.
Read the original research paper here: DOI: 10.1126/sciadv.abb6603
Plants communicate at a molecular level
Tomatoes can identify the parasitic vine dodder, Cuscuta spp., as an invader. Dodders do not make chlorophyll so they cannot make their own food. Instead the sneaky plant grafts itself to a tomato or other host plant using special suckers. It steals water, carbohydrates (sugars) and minerals from the host plant. Since dodder can not make its own energy it depends totally on other plants. Dodders do not kill their host but they weaken it. These plant parasites are found in every state.
Researchers found that tomatoes have special receptors in their cell walls that recognize the molecular protein pattern of the dodder (Hegenauer et al. 2020). This triggers the tomato's immune reaction and enables the tomato to fight back against the dodder. This knowledge may help plant breeders select for tomatoes with more resistance to dodder.
Read the research paper and see pictures here: DOI: 10.1038/s41467-020-19147-4
Volker H, Slaby P, Körner M, et al. The tomato receptor CuRe1 senses a cell wall protein to identify Cuscuta as a pathogen. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-19147-4
Origin story of 'lost crops' is revealed in the tracks of bison
One of the mysteries of agriculture is why people started relying on small unappetizing seeded grains for food instead of larger colorful fruits and juicy tubers. These plants offered a low caloric return for a lot of labor. Now this question has been answered. Ancient people gathered small seeded native plants and barley because they thrived in the prairie tracks left by herds of bison. These so called 'lost crops' were easy to see and find as people migrated in the tracks left by massive herds of buffalo through tall grass prairies.
Bison are big powerful animals. Grazing bison prune grasses, churn up soil with their hooves, add copious amount of natural fertilizer, and make large dirt wallows. This activity creates plant and soil disturbances that open up ideal habitats for annual forbs and grasses.
As people moved across the prairie they followed the bison trails and encountered large strands of the opportunistic plants. Some of these plants only occur in close relationship with grazing herds. Indigenous peoples domesticated many of these plants and maintained the vast prairies. Together, people and bison helped create a biodiverse landscape rich in food for all.
For more on this topic see Secrets of the 'lost crops' revealed where bison roam.