Spread Of Tomato Yellow Leaf Curl Virus Research Articles

Biological Invasions of Begomoviruses: A Case Study of TYLCV and Bemisia tabaci in Oman

This review article provides an in-depth analysis of the biological invasions of begomoviruses, focusing on a prominent case study involving the Tomato Yellow Leaf Curl Virus (TYLCV) and its vector, the whitefly Bemisia tabaci, in the unique agricultural landscape of Oman. Begomoviruses, known for their global impact on crop yields, have become a significant concern in Oman, posing a serious threat to the cultivation of various crops, particularly tomatoes. The review begins by exploring the molecular characteristics and ecological dynamics of TYLCV and Bemisia tabaci, shedding light on the intricate interactions between the virus, the vector, and the host plants. Through a comprehensive analysis of historical data and recent research findings, the article examines the patterns and pathways of invasion, elucidating the factors contributing to the successful establishment and spread of TYLCV in Oman. The impacts of TYLCV invasion on agricultural productivity and crop quality are critically evaluated, providing insights into the specific challenges faced by Omani farmers. Special attention is given to the socio-economic repercussions of TYLCV-induced crop losses, emphasizing the need for adaptive management strategies to mitigate the negative consequences on food security and rural livelihoods. Furthermore, the review assesses the current state of knowledge regarding the management and control of TYLCV and Bemisia tabaci in Oman. It discusses the successes and limitations of existing strategies, ranging from conventional practices to innovative biotechnological approaches, providing a foundation for future research directions and the development of sustainable management practices in the context of biological invasions of begomoviruses in Oman. Overall, this review contributes to a nuanced understanding of the complex interplay between invasive begomoviruses, their vectors, and local agricultural systems, offering valuable insights for researchers, policymakers, and practitioners engaged in crop protection and biosecurity in Oman and beyond.

Virus Accumulation and Whitefly Performance Modulate the Role of Alternate Host Species as Inoculum Sources of Tomato Yellow Leaf Curl Virus.

Evaluating alternate hosts that facilitate the persistence of a virus in the landscape is key to understanding virus epidemics. In this study, we explored the role of several plant species (eggplant, pepper, and Palmer amaranth) as inoculum sources of tomato yellow leaf curl virus (TYLCV) and as reservoirs for its insect vector, Bemisia tabaci (Gennadius). All inoculated species were infected with TYLCV, but whiteflies acquired fewer viral copies via feeding from pepper and eggplant than from tomato and Palmer amaranth. Further, back-transmission assays to recipient tomato resulted in TYLCV infection only when TYLCV was acquired from Palmer amaranth or tomato. Analysis suggested that the role of plant species as TYLCV inoculum sources may be determined by the accumulation of viral copies in the plant, and consequently in the insect vector. In addition, results showed that all three alternate species could sustain populations of B. tabaci, while differentially influencing fitness of whiteflies. Eggplant was a superior host for whiteflies, whereas whitefly survival was compromised on pepper. Together, we demonstrate that both plant-virus and plant-vector interactions could influence the role of an alternate host in TYLCV epidemics, and in our region of study we highlight the potential risk of hosts such as Palmer amaranth in the spread of TYLCV.

Suppressive effect of acetylated glyceride (Bemidetach™EC) on Tomato yellow leaf curl virus transmitted by the whitefly Bemisia tabaci on greenhouse tomato plants

Acetylated glyceride (Bemidetach™EC)—a food additive—repels adult sweet potato whiteflies (Bemisia tabaci) and inhibits their mating behavior. We evaluated the effects of acetylated glyceride spraying of greenhouse-grown tomato plants on infestation with B. tabaci and the occurrence of Tomato yellow leaf curl virus (TYLCV) disease under commercial-like conditions. The abundance of adult B. tabaci was significantly reduced by three sprayings of acetylated glyceride, and the TYLCV incidence was significantly suppressed to less than 30% of that in the untreated control. These results suggest that acetylated glyceride sprays suppress the secondary spread of TYLCV in greenhouse-grown tomatoes by lessening B. tabaci adult density.

Rapid Spread of a Recently Introduced Virus (Tomato Yellow Leaf Curl Virus) and Its Vector <I>Bemisia tabaci</I> (Hemiptera: Aleyrodidae) in Liaoning Province, China

In Liaoning Province, China, tomato yellow leaf curl virus (TYLCV) was first detected in 2009 and in only four counties. To quantify the spread of TYLCV and to identify potential factors influencing its spread in Liaoning Province, we assayed for TYLCV within 1,055 whiteflies (Bemisia tabaci (Gennadius) complex) from 74 populations and 29 counties in 2011. The B. tabaci species of these individuals was determined based on molecular markers. TYLCV was found in 13 counties (Donggang, Liaoyang, Kazuo, Lingyuan, Heishan, Liaozhong, Kaiyuan, Taian, Dawa, Dashiqiao, Beizhen, Linghai, and Xingcheng) and was most frequently detected in the central plain. In addition, the percentage of whiteflies with TYLCV was significantly higher in B. tabaci Q than in B. tabaci B but was unrelated to the hosts (pepper, eggplant, tomato, cucumber, and kidney bean) on which the whiteflies had been collected. These results demonstrate that TYLCV has spread rapidly in Liaoning Province since its first detection and suggest that its spread is more closely associated with the introduction of B. tabaci Q than with the species of host plant. These findings also indicate that controls are now needed to reduce the further spread of TYLCV and that these controls should include the management of B. tabaci Q populations.

Relationship of Whitefly Population Build up with the Spread of TYLCV on Eight Tomato Varieties

The performance of eight tomato varieties namely BARI-T1 (Manik), BARI-T2 (Ratan), BARI-T4, BARI-T5, BARI-T6 (Apurba), BARI-T7 (Chaity), BARI-T11 and BARI-T12 were evaluated in respect to prevalence and spread of TYLCV (Tomato Yellow Leaf curl Virus) in relation to whitefly population buildup in the field. Data were collected on the three growth stages of the plant namely early (transplanting to first flowering) mid (first flowering to first harvesting) and late (first harvesting to last harvesting). The virus prevalence percentage in eight tomato varieties varied depending on early, mid and late stage of infection as well as tomato varieties. It ranged from 42 to 69%. There was a poor and insignificant quadratic polynomial relationship (y = -0.0059x 2 + 0.2826x – 1.5378 & R2 = 0.0962) between temperature and whitefly population build up in tomato field. The relationship between relative humidity and whitefly population build up in the field was found significant but negatively correlated (y = - 0.0321x 2 +4.5518x – 159.44 (R2 = 0.6769). The increase of whitefly population in the field was positively correlated with the spread of TYLCV in the tomato field (y = - 0.0002x 2 + 0.0297x + 1.0626 & R2 = 0.663). The highest and lowest prevalence of TYLCV was recorded in BARI-T6 and BARI-T11, respectively. In all the varieties, virus prevalence was found higher at mid stage followed by late and early stage of infection. 
 
 Key words: Prevalence, TYLCV, whitefly.