Extracts of Common Pesticidal Plants Increase Plant Growth and Yield in Common Bean Plants

Abstract

Common bean (Phaseolus vulgaris) is an important food and cash crop in many countries. Bean crop yields in sub-Saharan Africa are on average 50% lower than the global average, which is largely due to severe problems with pests and diseases as well as poor soil fertility exacerbated by low-input smallholder production systems. Recent on-farm research in eastern Africa has shown that commonly available plants with pesticidal properties can successfully manage arthropod pests. However, reducing common bean yield gaps still requires further sustainable solutions to other crop provisioning services such as soil fertility and plant nutrition. Smallholder farmers using pesticidal plants have claimed that the application of pesticidal plant extracts boosts plant growth, potentially through working as a foliar fertiliser. Thus, the aims of the research presented here were to determine whether plant growth and yield could be enhanced and which metabolic processes were induced through the application of plant extracts commonly used for pest control in eastern Africa. Extracts from Tephrosia vogelii and Tithonia diversifolia were prepared at a concentration of 10% w/v and applied to potted bean plants in a pest-free screen house as foliar sprays as well as directly to the soil around bean plants to evaluate their contribution to growth, yield and potential changes in primary or secondary metabolites. Outcomes of this study showed that the plant extracts significantly increased chlorophyll content, the number of pods per plant and overall seed yield. Other increases in metabolites were observed, including of rutin, phenylalanine and tryptophan. The plant extracts had a similar effect to a commercially available foliar fertiliser whilst the application as a foliar spray was better than applying the extract to the soil. These results suggest that pesticidal plant extracts can help overcome multiple limitations in crop provisioning services, enhancing plant nutrition in addition to their established uses for crop pest management.

Growth Promotion, Nutrition Levels, and Antioxidant Activity in Peucedanum japonicum Thunb. under Various Plant Extracts

“…Nevertheless, the total flavonoid contents in the Peucedanum japonicum leaves were similar when treated with the soybean stem, Chinese chive, onion, and tomato extracts. In another study, the flavonoid contents increased in the Tithonia diversifolia-treated tomato plants [34]. Similarly, neem (Azadirachta indica) extracts applied to tomatoes have been observed to increase the abundance of several flavonoids through the jasmonate pathway [35].…”

An introduction of fall armyworm (Spodoptera frugiperda) with management strategies: a review paper

“…The seed cake extract of Azadirachta indica (Silva et al, 2015) and ethanolic extracts of Argemone ochroleuca (Martinez et al, 2017) cause high mortality of FAW larva due to reduction of food intake by larvae resulting slower growth. As the botanical pesticides have lesser effect on the non-target organisms and have an ability to add in growth promotion some of the pesticidal plants, they are found effective with reduce in use of synthetic insecticides (Abudulai et al, 2001;Mkindi et al, 2020;Rioba et al, 2020). Ageratum conyzoides (Lima et al, 2010;Rioba and Stevenson, 2017), Chenopodium ambrosioides has been evaluated for their efficacy against fall armyworm (Sisay et al, 2019;Rioba et al, 2020).…”

Involvement of Allelopathy in the Invasive Potential of Tithonia diversifolia

“…Both treatments enhanced the growth and yield of the beans. The enhancements were considered to be consequences of the increasing the concentrations of chlorophyll and metabolites in the bean plants, such as phenylalanine and tryptophan [ 27 ]. The extracts and residues of T. diversifolia also worked as fertilizers because of their high mineral values [ 8 , 10 , 11 ].…”