Better Way to See Whitefly Eggs on Different Plants

Jenn Hoskins
24th May, 2024

Better Way to See Whitefly Eggs on Different Plants

To standardize the conditions for whitefly oviposition assays, this figure illustrates the consistent placement of clip cages (a, b) on the third or fourth suitable leaf from the plant's growing tip across all tested crop species (c, d).

Image adapted from: Raalte et al. / CC BY (Source)

Key Findings

  • Researchers at the University of California, Riverside, developed a staining method to better visualize sweet potato whitefly eggs on crops
  • The staining process increased egg counts for less experienced counters across all tested crops and for more experienced counters on melons, tomatoes, and cowpeas
  • This method improved agreement on egg counts between different counters, aiding in the accurate assessment of crop resistance to whiteflies
The sweet potato whitefly (Bemisia tabaci) is a significant pest that causes extensive damage to crops not only through direct feeding but also by transmitting viruses. Managing this pest typically involves using insecticides, which are costly and environmentally damaging. An alternative approach is to develop crop varieties resistant to B. tabaci, but progress has been hindered by the high cost and low throughput of screening plants for resistance. A critical metric for assessing resistance is the oviposition rate, which measures the number of eggs laid by the pest on the plant. However, accurately counting these microscopic and translucent eggs has been challenging. Researchers at the University of California, Riverside, aimed to address this issue by improving the quantification of B. tabaci eggs on several important crop species: cassava, cowpea, melon, sweet potato, and tomato[1]. They tested a selective staining process initially developed for leafhopper eggs to see if it could enhance the visibility of B. tabaci eggs. The staining process involved submerging the leaves in McBryde's stain for three days, followed by clearing the leaves under heat and pressure for 15 minutes in a clearing solution. The results were promising. For a less experienced counter, egg counts increased after staining across all five crops. For a more experienced counter, egg counts increased on melons, tomatoes, and cowpeas. Additionally, there was significantly greater agreement on egg counts between the two individuals after the staining process. This method proved particularly effective on melons, where egg counts universally increased for both counters. This new staining method has broad applications, especially in research areas requiring accurate quantification of B. tabaci eggs, such as phenotyping for resistance. By improving the visualization of these eggs, the method can accelerate the development of resistant crop varieties, reducing reliance on insecticides. The findings build on previous research on whitefly management and plant resistance. For instance, a study on zucchini plants found that high whitefly infestations reduced fruit yield and quality, regardless of the plant's tolerance to squash silverleaf disorder[2]. This highlights the importance of developing resistant crop varieties to mitigate the impact of whiteflies. Another study examined the Mi-1 gene in tomatoes, which mediates resistance to B. tabaci and other pests[3]. The new staining method could facilitate the identification of resistant tomato varieties, furthering the goals of such research. Moreover, the development of automated tools for quantifying whitefly eggs, like the Eggsplorer application, has shown that technological advancements can significantly aid in resistance screening[4]. The staining method complements these tools by providing a reliable way to visualize eggs, which can then be quantified more accurately, whether manually or through automated systems. In conclusion, the selective staining method developed by researchers at the University of California, Riverside, represents a significant advancement in the fight against B. tabaci. By improving the accuracy and reliability of egg counts, this method can accelerate the development of resistant crop varieties, offering a sustainable solution to managing this pervasive pest.

AgriculturePlant ScienceAnimal Science

References

Main Study

1) Evaluation of a low-cost staining method for improved visualization of sweet potato whitefly (Bemisia tabaci) eggs on multiple crop plant species.

Published 23rd May, 2024

https://doi.org/10.1186/s13007-024-01209-z

Related Studies

2) Impact of Bemisia argentifolii (Homoptera: Auchenorrhyncha: Aleyrodidae) infestation and squash silverleaf disorder on zucchini yield and quality.

Journal: Journal of economic entomology, Issue: Vol 97, Issue 6, Dec 2004

3) Effect of plant development (age and size) on the Mi-1-mediated resistance of tomato to whitefly Bemisia tabaci.

https://doi.org/10.1017/S0007485317000281

4) Eggsplorer: a rapid plant-insect resistance determination tool using an automated whitefly egg quantification algorithm.

https://doi.org/10.1186/s13007-023-01027-9


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