Episodes
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Every year we get asked whether lady bugs can be used to manage pests. In this episode, we discuss a review paper on the effectiveness of exotic lady beetles to manage insect pests, but we'll also discuss the use of lady beetles in biological control in general.
Randoni et al. (2020). Exotic ladybirds for biological control of herbivorous insects – a review. Entomologia Experimentalis et Applicata 169: 6 - 27.
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A new invasive snail has been observed near Miami (Florida) in August of 2020. If established, the snail can be problematic in nursery, greenhouse, fruit and vegetable production. Recognition is vital - if you see this snail, please report to state regulatory agencies right away (i.e. Texas Department of Agriculture). We also talk about the practical challenges with growing plants on Mars; something we're all going to encounter in the next 5 years or so... probably.
Horntail Snail: https://www.fdacs.gov/content/download/93400/file/horntail-snail-pest-alert.pdf
Growing plants on Mars: https://www.sciencenews.org/article/mars-farming-harder-martian-regolith-soil
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Episodes manquant?
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ACC, or more commonly known as 1-Aminocyclopropane-1-carboxylic acid on the streets, is a precursor to ethylene, the compound most known for its ability to ripen fruit. ACC was not thought to have its own set of functions, but this recent article supports otherwise. A better understanding of plant physiology can lead to a whole new area of plant research, which includes potential management strategies.
Citation:
Van de Poel, B. 2020. Ethylene’s fraternal twin steals the spotlight. Nat. Plants. 1–2.
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I've received reports of large migrations of whiteflies recently in the landscape, from Dallas, Austin and even east Texas regions. It's not uncommon to see large clouds of whiteflies when cotton is 'defoliated' in preparation for harvest; however, whiteflies often need some time to get used to their new plant host (acclimation). Changes in endosymbionts, bacteria found inside the insect that commonly have a mutualistic positive relationship with the insect, are a potential explanation for host shift acclimation. For fun, we also talk about the diabolical ironclad beetle and it's incredibly resilient properties that make engineers interested enough to study.
Some references:
Asplen, M. K., N. Bano, C. M. Brady, N. Desneux, K. R. Hopper, C. Malouines, K. M. Oliver, J. A. White, and G. E. Heimpel. 2014. Specialisation of bacterial endosymbionts that protect aphids from parasitoids. Ecol. Entomol. 39: 736–739.
Hu, F.-Y., and C.-W. Tsai. 2020. Nutritional relationship between Bemisia tabaci and its primary endosymbiont, Portiera aleyrodidarum, during host plant acclimation. Insects. 11: 1–13.
Liu, X. D., and H. F. Guo. 2019. Importance of endosymbionts Wolbachia and Rickettsia in insect resistance development. Curr. Opin. Insect Sci. 33: 84–90.
Kanakala, S., and M. Ghanim. 2019. Global genetic diversity and geographical distribution of Bemisia tabaci and its bacterial endosymbionts. PLoS One. 14.
Weinert, L. A., E. V. Araujo-Jnr, M. Z. Ahmed, and J. J. Welch. 2015. The incidence of bacterial endosymbionts in terrestrial arthropods. Proc. R. Soc. B Biol. Sci. 282: 3–8.
Vorburger, C. 2018. Symbiont-conferred resistance to parasitoids in aphids – Challenges for biological control. Biol. Control. 116: 17–26.
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The Asian Giant Hornet is one of the many plagues that's hit us in 2020; but as fall approaches, it's thought they will enter the slaughter phase, when they can take out an entire bee hive within hours. Fortunately for us in Texas, recent models suggest that the the Asian Giant Hornet won't establish in Texas due to our suboptimal climate (and because they take "Don't mess with Texas" seriously).
We also discuss new findings on the importance of plant guttation as a nutritional resource for insects and the potential implications for systemic insecticides.
Citations:
Matsuura, M., and S. F. Sakagami. 1973. A bionomic sketch of the giant hornet, Vespa mandarinia, a serious pest for Japanese apiculture. 北海道大學理學部紀要. 19: 125–162.
University of Melbourne. 2020. 'Insect Armageddon': Low doses of the insecticide, Imidacloprid, cause blindness in insects: Findings show even small doses of insecticides reduce capacity of insects to survive. ScienceDaily. ScienceDaily, 28 September 2020. <www.sciencedaily.com/releases/2020/09/200928152916.htm>.
Urbaneja-Bernat, P., A. Tena, J. González-Cabrera, and C. Rodriguez-Saona. 2020. Plant guttation provides nutrient-rich food for insects. Proceedings. Biol. Sci. 287: 20201080.
Zhu, G., J. Gutierrez Illan, C. Looney, and D. W. Crowder. 2020. Assessing the ecological niche and invasion potential of the Asian giant hornet. Proc. Natl. Acad. Sci. 0: 202011441.
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Increasing levels of CO2 is one of the driving factors for global climate change. This same CO2 also happens to be vital for plant growth via photosynthesis. As a result, fast-growing plants, such as poison ivy, are actually becoming more abundant and more hazardous.
https://www.southernliving.com/news/poison-ivy-more-poisonous-bigger-climate-change?fbclid=IwAR24gBcp2fknpLYUcnG6IDvLEndKF6RyMhAUqFDgYiWbpoSWsHIN0kXll3A
If you were eaten by a frog, how would you survive? Well, these water beetles survive by swimming 'downstream'.
https://www.sciencenews.org/article/water-beetle-frog-eaten-alive-escape-death-butt-excretion?fbclid=IwAR2OhiL1E6IEqQs6ZjoK_ukVoL82-Ikx-zJaaUqkdO7_wnvKuprSOzcjt6Q
And lastly, here is a link to provide you nightmares of swarms of fungus gnat larvae.
https://www.youtube.com/watch?v=6MwYvLaJ6Ho
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Potted plants are arguably overwatered in the greenhouse and nursery industry. Over-watering can be considered a waste of water, results in leaching of pesticides and fertilizers, and can promote plant pathogens. In this episode, we discuss a study that uses various sensors to assess plant stress to determine how much watering can be reduced before the plant is 'too stressed'.
For the full article:
Nackley, L. L., E. Fernandes de Sousa, B. J. L. Pitton, J. Sisneroz, and L. R. Oki. 2020. Developing a Water-stress Index for Potted Poinsettia Production. HortScience. 55: 1295–1302.
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A common assumption is that ornamental plants must be perfectly clean when they hit the retailer. No pests. Nada. This assumption is unrealistic and rather harmful. By making this assumption, we limit our pest management decisions to options that are most likely to kill all the insects: synthetic insecticides. However, how true is it that synthetic insecticides give us perfectly clean plants? And if "zero" pests is unrealistic, what is? Listen to this episode to learn more about a study looking at whitefly densities on poinsettia cuttings received by growers and finished poinsettias that make it to the retailer.
Citation:
Vafaie, E. K., H. B. Pemberton, M. Gu, D. Kerns, M. D. Eubanks, and K. M. Heinz. 2020. Whitefly Abundance on Rooted Poinsettia Cuttings and Finished Poinsettias. Horttechnology. 1–6.
https://journals.ashs.org/horttech/view/journals/horttech/30/4/article-p486.xml
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We often associated federal crimes with illegal drugs, guns or human trafficking, but rarely do we consider that selling plants and insects can be illegal, especially if imported without a permit. In this episode, we discuss two popular science articles that discuss federal investigations into plant and insect smugglers.
Full articles:
Jani Actman (2019). Demand for exotic pets and collectors' items drives a flourishing illegal trade in beetles, spiders, and more. National Geographic: Wildlife Watch.
Rob Walker (2020). Texas's cactus cops battle to save rare desert beauty from smuggling gangs. The Guardian.
John MacCormack (2020). Smugglers sold thousands of protected "living rock" cacti, found only in the Big Bend. San Antonio Express News.
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The cucumber mosaic virus is a plant virus vectored by aphids. The virus can decrease yields, which would ultimately result in the plant produce less progeny. In a natural environment, we would expect high virus pressure to quickly result in selection for virus-resistant plants. However, the virus counteracts the negative impact on plant fertility by manipulating plant physiology to make it more attractive to pollinators!
Full citation below:
Groen, S.C., Jiang, S., Murphy, A.M., Cunniffe, N.J., Westwood, J.H., Davey, M.P., Bruce, T.J.A., Caulfield, J.C., Furzer, O.J., Reed, A., Robinson, S.I., Miller, E., Davis, C.N., Pickett, J.A., Whitney, H.M., Glover, B.J., Carr, J.P., 2016. Virus Infection of Plants Alters Pollinator Preference: A Payback for Susceptible Hosts? PLoS Pathog. 12, 1–28. https://doi.org/10.1371/journal.ppat.1005790
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The soil harbors all kinds of fungi; some beneficial and some detrimental to the health of plants. A specific class of fungi, known as arbuscular mycorrhizal fungi (AMF) form a symbiotic relationship with the roots of plants that's associated with over 80% of plant species globally. These fungi can help alter plant defense traits against herbivores or help provide nutrients to plants. In episode, we digest a study specific to AMF of milkweed plants and how it can impact performance of monarch butterfly caterpillars and aphids.
Full citation to study:
Meier, A. R., & Hunter, M. D. (2018). Mycorrhizae alter toxin sequestration and performance of two specialist herbivores. Frontiers in Ecology and Evolution, 6: 1 - 16.
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Mr. Stanton Gill wrote an article in GrowerTalks (https://www.growertalks.com/Article/?articleid=24625) entitled Basil Downy Mildew Field Observations. We'll discuss some of is main discussion points there, from when it first showed up in the USA, symptoms, and resistant cultivars.
In some forests, tree canopies exhibit an interesting behavior in which the leaves and branches will form a 'jigsaw'-like pattern, with leaves and branches avoiding actually touching. Several hypotheses have been expressed for why this happens which is explored in a JSTOR Daily article that we discuss together (https://daily.jstor.org/the-mysteries-of-crown-shyness/?fbclid=IwAR1zcGk5tY5_EK8TXVeKMGgb51K7WWaVa6GuQipKD-xheR4rNMxlHbW7rSw)
Lastly, Vikram and Erfan have a heart-to-heart about why horticulturalists hate on Bradford pears so much!
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The mountain pine beetle is a devastating pest of pine forests in the west coast of North America. The beetle will bore into and kill healthy trees, much like the Emerald Ash Borer that has recently been detected in Texas. In this episode, we explore how one tree species, the bristlecone pine, is able to defend against the mountain pine beetle.
Full citation of article discussed:
Bentz, B.J., Hood, S.M., Hansen, E.M., Vandygriff, J.C. and Mock, K.E. (2017), Defense traits in the long‐lived Great Basin bristlecone pine and resistance to the native herbivore mountain pine beetle. New Phytol, 213: 611-624. doi:10.1111/nph.14191
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Learn a bit about the two hosts of the show, Erfan Vafaie and Vikram Baliga, how their aspirations to become medical doctors led to become lowly poor scientists, and how they found their passion for insects sand plants.
In this episode, we also digest an article by Szczepaniec and colleagues (2013) that seeks to understand a commonly observed phenomena; some plants treated with neonicotinoid insecticides appear to increase in spider mite populations.
Neonicotinoids are a class of insecticides that include imidacloprid, dinotefuran, and thiamethoxam (to name a few) and are considered systemic; applications to the soil are taken up by the roots and provide protection from insects feeding on the plant. Unnecessary applications are not only costly, but can have unintended consequences!
Full citation of article discussed:
Szczepaniec, A., M.J. Raupp, R.D. Parker, D. Kerns and M.D. Eubanks. 2013. Neonicotinoid insecticides alter induced defenses and increase susceptibility to spider mites in distantly related crop plants. PLoS One. 8.
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On this show, we'll digest data from scientific research and popular science magazines (such as GrowerTalks) related to horticultural sciences; whether we're talking about insects or plant production practices. The two hosts are:
Erfan Vafaie, Extension Program Specialist II, Texas A&M AgriLife Extension Service
Vikram Baliga, Greenhouse Manager and Instructor of Horticulture, Texas Tech University
