**6.2 Biotic constraints**

Biotic constraints include insect pests and diseases: Insect pests of sweet potato are weevils, nematodes, sweet potato butterfly, millipedes, and rats [20, 21]; diseases include stem blight [22], Fusarium wilt, bacterial wilt, black spot, root rot, and virus diseases [21].

### **6.3 Management constraints**

They are: poor awareness about improved sweet potato varieties and the production of healthy, disease-free planting materials [2]; absence of rainwater harvesting in rain-fed areas and poor management of irrigation water in irrigated areas; and other agronomic constraints such as poor land preparation, use of local varieties and poorquality vine cuttings, late planting, inadequate pest and disease control, and inefficient postharvest management.

#### **6.4 Socio-economic constraints and opportunities**

Smallholders face several problems in terms of agro-ecological, economic, institutional, and social contexts. These are also called as commodity value chain challenges, constraints and opportunities by [23]. Sweet potato production is seasonal as dictated by local weather; farmers' poor access to capital and markets; poor agricultural extension support to farmers, particularly with respect to timely distribution of improved varieties and good-quality planting materials at the start of the season; farmers' inability to buy and apply fertilizers; high postharvest losses (40–80%) linked inefficient handling, storage, and transport of bulky sweet potato roots from farms to markets or processing centres [23–25]; low profit due to increasing production costs and decreasing revenue due to poorly developed markets for sweet potato and low farmgate price at peak harvest periods [26]; and low or no availability of safe storage and processing industries in rural production zones.
