12 research outputs found
Potato virus Y: Control, Management and Seed Certification Programmes
The management of Potato virus Y (PVY) in potato crops poses a continual challenge due to the non-persistent mode of transmission of the virus and the propagation of seed potato tubers over several generations in the field. While PVY-resistant cultivars remain the most efficient way to protect potato crops against PVY, a vast majority of cultivars grown do not display significant resistance to PVY. Due to the short time period for PVY transmission by non-colonising aphid vectors, efficient control of PVY relies on preventing aphids landing on a crop and on adopting precautionary measures by ensuring that crops are grown in areas of low aphid and low virus pressure and limiting field generation. Prophylactic measures such as roguing and early haulm destruction limit PVY spread but are not efficient alone. Among all existing control methods, spraying potato crops with mineral oils can offer significant protection against PVY spread, but their efficacy do vary in field conditions. The combination of several control methods such as mineral oil treatments, crop borders, intercropping, straw mulching or insecticide treatments can increase protection. These emphasise the importance of controlling virus through appropriate monitoring methods and crop management enforced by seed certification schemes through the use of ‘clean’ input seed and, when possible, the segregation of seed and ware crops to minimise the risk of virus transmission. This chapter presents and discusses the most widely used techniques of control and management of PVY, their effectiveness and their mode of action. This chapter also presents the history, objectives and principles of seed potato certification schemes and their role in minimising the spread of viruses within potato crops worldwide
The role of visual and olfactory plant cues in aphid behaviour and the development of non-persistent virus management strategies
The review was part of M. L. Schroder’s PhD
thesis that was undertaken at the University of Pretoria (UP) in collaboration
with the Swedish University of Agricultural Sciences
(SLU).Non-persistent viruses are transmitted by aphids in short feeding probes
during the initial stages of aphid host plant selection behaviour. To control
the transmission of these viruses, farmers rely on pesticides and cultural
control practices, with varying success rates. As a result, there is a need for
novel management practices that are more robust and specific to reducing
aphid landing rates in crops. Aphid–plant–virus interactions involve a
number of behaviours and processes to ensure survival of the insect vector
and virus. So far, virus management tactics focused on reducing
immigrating aphids in crops have emphasized the manipulation of visual rather than olfactory stimuli. An improved understanding of the synergistic
or additive effects in which aphids use visual and olfactory stimuli to locate
host plants could be used to improve on current non-persistent virus
management tactics and develop novel strategies. The aim of this review is
to evaluate current understanding of aphid vector behaviour and the ways
that these behaviours have been exploited to develop management
strategies, and to identify areas of research needed to further improve virus
management.Potatoes South Africa
(PSA), the Technology and Human Resources for Industry Programme
(THRIPP), the National Research Foundation (NRF) and the
University of Pretoria.http://link.springer.com/journal/118292018-02-28hb2017Zoology and Entomolog