by K.L. Heong
International Rice Research Institute, Los Baños, Philippines
When partners of the Rice Planthopper project met at the Inception meeting in November 2008, they designed the project logo (see above). The background of the logo is the yin-yang symbol. In Oriental philosophy, the concept of yin yang (yin – 陰; yang – 陽 ) is often used to describe how opposing forces are interconnected and interdependent in the natural world. The concept is the primary guideline of traditional Chinese medicine and a central principle of Chinese martial arts and exercise, such as taijiquan, and qigong.
Yin and Yang are complementary opposites within a greater whole thus most things have both yin and yang aspects that constantly interact. For instance, winter is yin to summer’s yang over the course of a year, and femininity is yin to masculinity’s yang in human relationships. Yin–yang is a dynamic equilibrium and is a universal way of describing the interactions and interrelations of the natural forces that occur in the world.
It is becoming evident that rice planthopper problems are not just a pest problem but a symptom of ecological breakdown. Typically r – strategists, planthoppers tend to multiply exponentially leading to outbreak conditions when released from natural enemy control or the yang forces. Thus rice production systems with compromised biological control ecosystem services, such as pest invasion resistance and pest regulation, become vulnerability to invading adults. Since planthoppers are generally monophagous, invading adults are likely to come from rice fields in the neighborhood or from long distances. Planthopper outbreaks tend to occur when the yin-yang equilibrium is shifted favoring the yin forces, such as biodiversity loss and excessive pesticide use. The yin-yang imbalance is usually caused by yin favoring structural systems and policies, such as weak pesticide regulation, incentives favoring short term gains and lack of incentives for sustainability and lacking in policies to support the conservation of ecosystem services. Such imbalance weakens many of the yang elements introduced by research, such as planthopper tolerant varieties, ecological engineering techniques, IPM, farmer training and pesticide reduction campaigns (see below). In some cases, the yang elements are cancelled out. For instance in Long An province where insecticide use was reduced by a media campaign, about 9 years later, farmers here had increased their applications.
Sustainable management of planthoppers in the future will require adjustments in structural systems to balance the yin and yang elements, which will include policy, structure and social reforms, introducing payment for environmental services (PES), pro green policies and regulations to prevent pesticide misuse. (see below). These adjustments will then be able to facilitate the implementation of yang elements, such as pest resistant varieties, ecological engineering approaches to enhance ecosystem services and IPM. In some countries, where the yin forces are in extremes, like China where pesticides are very cheap, some of them sold in > 500 trade names and extension officials earn their incomes from pesticide sales, rather drastic reforms might be needed.