The greenhouse thrips (Heliothrips haemorrhoidalis) is a serious pest of fruits and ornamental plants. In the Morris Arboretum’s greenhouse complex, this thrip has been prevalent, and could cause major damage to the young plants that are being propagated. The purpose of this project was to search for a suitable biological control of the thrips since chemicals have only been marginally effective. A predatory spider mite (Amblyseius cucumeris) and minute pirate bugs (Orius insidiousus) were chosen for the study. The results suggest that the minute pirate bugs are highly effective at hunting thrips, while the spider mites had no measurable effect

Quadrel, Amanda

English

ScholarlyCommons@Penn

University of PennsylvaniaScholarlyCommonsInternship Program Reports Education and Visitor Experience2018Testing Biological Controls for Heliothripshaemorrhoidalis (Thysanoptera: Thripidae), aSerious Pest of the Morris Arboretum GreenhouseComplexAmanda QuadrelUniversity of PennsylvaniaFollow this and additional works at: https://repository.upenn.edu/morrisarboretum_internreportsPart of the Botany CommonsAn independent study project report by The John J. Willaman and Martha Haas Valentine Endowed Plant Protection Intern (2017-2018)This paper is posted at ScholarlyCommons. https://repository.upenn.edu/morrisarboretum_internreports/1For more information, please contact repository@pobox.upenn.edu.Recommended CitationQuadrel, Amanda, "Testing Biological Controls for Heliothrips haemorrhoidalis (Thysanoptera: Thripidae), a Serious Pest of the MorrisArboretum Greenhouse Complex" (2018). Internship Program Reports. 1.https://repository.upenn.edu/morrisarboretum_internreports/1Testing Biological Controls for Heliothrips haemorrhoidalis (Thysanoptera:Thripidae), a Serious Pest of the Morris Arboretum Greenhouse ComplexAbstractThe greenhouse thrips (Heliothrips haemorrhoidalis) is a serious pest of fruits and ornamental plants. In theMorris Arboretum’s greenhouse complex, this thrip has been prevalent, and could cause major damage to theyoung plants that are being propagated. The purpose of this project was to search for a suitable biologicalcontrol of the thrips since chemicals have only been marginally effective. A predatory spider mite (Amblyseiuscucumeris) and minute pirate bugs (Orius insidiousus) were chosen for the study. The results suggest that theminute pirate bugs are highly effective at hunting thrips, while the spider mites had no measurable effect.DisciplinesBotanyCommentsAn independent study project report by The John J. Willaman and Martha Haas Valentine Endowed PlantProtection Intern (2017-2018)This report is available at ScholarlyCommons: https://repository.upenn.edu/morrisarboretum_internreports/1 1 TITLE: Testing Biological Controls for Heliothrips haemorrhoidalis  (Thysanoptera: Thripidae), A Serious Pest of the Morris Arboretum Greenhouse Complex  AUTHOR: Amanda Quadrel,  The John J. Willaman and Martha Haas Valentine Endowed Plant Protection Intern  ABSTRACT:    The greenhouse thrips (Heliothrips haemorrhoidalis) is a serious pest of fruits and ornamental plants. In the Morris Arboretum’s greenhouse complex, this thrip has been prevalent, and could cause major damage to the young plants that are being propagated. The purpose of this project was to search for a suitable biological control of the thrips since chemicals have only been marginally effective. A predatory spider mite (Amblyseius cucumeris) and minute pirate bugs (Orius insidiousus) were chosen for the study. The results suggest that the minute pirate bugs are highly effective at hunting thrips, while the spider mites had no measurable effect.                             2 Table of Contents Introduction: ................................................................................................................................... 3 Methodology: ................................................................................................................................. 3 Part I: Rearing thrips for the study ......................................................................................................... 3 Part II: Implementing the controls ......................................................................................................... 4 Results: ........................................................................................................................................... 4 Table 1: Total sum of thrips for each week .......................................................................................... 4 Table 2: Average number thrips/plant .................................................................................................. 4 Figure 1: Rate of thrips population growth based on average number of thrips per trial ..................... 4 Discussion: ..................................................................................................................................... 5 References:..................................................................................................................................... 6                                3 INTRODUCTION   The greenhouse thrips, Heliothrips haemorrhoidalis Bouche, is a serious pest of various ornamental and crop plants. Originally a native to South America, the insect was transported to Europe, and then North America via tropical plant movement. In the United States, the thrips can be found outdoors on wild and cultivated plants. In the northern states, however, the winter climate is too cold for the thrips to survive, thus they are more commonly found inside greenhouses or in other interior plantscapes (Stevens et al. 1999).   The larvae of H. haemorrhoidalis are pale yellow with red eyes. As they mature, they turn black bodied with yellow legs, and the fringed forewings visibly converge dorsally. Greenhouse thrips have piercing-sucking mouthparts that they use for sucking sap out of plant tissues (Polilov and Shmakov 2016). Another important characteristic of this thrip is that it excretes a black liquid that is often deposited on the surfaces of the leaves. When the population grows large, damage from these thrips cause the leaves to turn a silver or brown color, and in severe cases, can cause leaves to drop prematurely. On fruit crops, the thrips can cause rind blemishes and fruit drop (Stevens et al. 1999).   At the Morris Arboretum, this species of thrip has been one of the most serious pests to plague the greenhouse complex. The need for treatment is especially dire due to the amount of young plants that are propagated in the greenhouse. If left unchecked, the thrips can cause an entire plant to die. Chemical controls such as spinosad have been used with varying effectiveness, but nothing has been able to provide adequate control; the pest has always resurged after a few weeks. This is probably because getting thorough coverage of the leaves is difficult, and the eggs are protected by the thrips’ excrement, rendering chemical controls ineffective against eggs. Biological controls may be a better case in this situation because predators or parasitoids can actively hunt for thrips and can possibly predate on multiple life stages. So far, only one effective biological control exists, but it is not yet commercially available (McMurty and Badii 1991). There are other, more general biological controls that have been studied, but few have been evaluated for their effectiveness against greenhouse thrips specifically. Therefore, for this project, the goal is to evaluate different biological control treatments for these thrips to prevent further damage. This study could potentially benefit other gardens in which thrips have become a problem.  Methodology:   Part I: Rearing thrips for the study  For the first part of this project, sufficient numbers of the pest had to be reared. To do this, small camellia seedlings (Camellia sinensis) were dug up from a site at the Arboretum and potted. These plants were kept in small isolation chambers to prevent the spread of the pest. Over the course of several months, thrips from around the greenhouses were collected and transferred onto the camellia seedlings and left undisturbed, except for occasional transferring of thrips to other plants to promote a more even spread.  Before the application of controls, the camellias were separated into three groups of eight reps, and the number of thrips on each plant was counted.   4 Part II: Implementing the controls   The next part of the project involved applying biological controls. Two control agents: Orius insidiousus (Hemiptera:Anthocoridae) and Neoseilus cucumeris (Acari:Phytoseiidae) were chosen based on their affinity for thrips. Activity of the control agents was measured based on how many thrips were on the camellia seedlings from week to week. The minute pirate bug, Orius insidiosus is a voracious predatory insect that purportedly has an affinity for thrips. The predatory mites, Neoseilus cucumeris have also been said to be effective predators of different thrips.   Results:   Table 1: Total sum of thrips for each week    Week 1 Week 2 Week 3 Week 4 Week 5 Control 183 187 89 39 158 Amblyseius 347 456 545 419 308 Orius 393 6 0 107 109  Table 2: Average number thrips/plant   Column1 Week 1 Week 2 Week 3  Week 4 Week 5 Control 22.875 23.375 11.125 4.875 19.75 Amblyseius 43.375 57 68.125 59.857 44 Orius 49.125 0.75 0 15.285 15.571  Figure 1: Rate of thrips population growth based on average number of thrips per trial  01020304050607080Week 1 Week 2 Week3 Week 4 Week 5Average Number of Thrips per PlantControl Amblyseius Orius 5  The results suggest that the minute pirate bugs, Orius insidiousus were the most effective biological control. This control method had a 100% success rate after two weeks of activity. The population of thrips started to resurge after week three, but that is likely due to the pirate bugs dying, and another application would swiftly take care of the problem. The spider mites seemed to have no effect on control of thrips at all, and the population continued to grow after the application of the mites. Discussion:  While this project is a good start for managing greenhouse thrips, there are still several limitations for the project that time did not allow to explore. There were also limitations to the amount of reps that could be completed due to time and resource constraints. Having more reps would make for a more statistically valuable study. The rearing process was problematic because it was difficult to get the insects to spread evenly across all the plants and the damage caused by the thrips would often cause the plants to die or completely defoliate within the incubation period.  There are also many research opportunities that can be explored beyond the scope of this project. For instance, using a combination of control methods is very important, as the insects can quickly develop resistance to just chemical controls. However, figuring out which chemical and biological controls are compatible with each other can be difficult and time consuming. Should this project be carried on further, one should create a program that combines different chemical and biological controls for more efficient control. Plus, there would need to be a more long-term monitoring program, since the pest can often resurge after some time.                         6 References:    1. Chhagan, A. and Stevens, P. S. 2007. Effect of temperature on the development, longevity, and oviposition of greenhouse thrips (Heliothrips haemorrhoidalis) on lemon fruit. New Zealand Plant Protection 60: 50-55. 2. Polilov, A. A., Shmakov, A. S. 2016. The anatomy of the thrips Heliothrips haemorrhoidalis (Thysanoptera: Thripidae) and its specific features caused by miniaturization. Arthropod Structure and Development 45: 496-507. 3. S. Allison, Brown, S. and Simmons, M. S. J. 2006. Leaf morphology of the hosts and non-hosts of Heliothrips haemorrhoidalis (Bouche). Bo. Jo. Lin. Soc. 152: 109-130.  4. Larral, P. and Ripa, R. 2007. Evaluation of pesticide effectiveness on the control of Heliothrips haemorrhoidalis (Thysanoptera, Thripidae) on avocado trees. Proc. VI World Avocado Congress 5. McMurty, J. A. and Badii, M. H. 1991. Greenhouse thrips (Heliothrips haemorrhoidalis) in avocado orchards: biological control studies.  6. Modeun, S., Sarmiento, K. S., Klinkhamer, P. G. L., and Leiss, K. A. 2017. Integrated pest management in western flower thrips; past, present, and future. Pest Manag. Sci. 73: 813-832.  7. Stevens P, Froud K, Mills E. 1999. Effects of greenhouse thrips (Heliothrips haemorrhoidalis) life-stage, density and feeding duration on damage to avocado fruit. Revista Chapingo Serie Horticultura 5: 297-300.    

Testing Biological Controls for \u3cem\u3eHeliothrips haemorrhoidalis\u3c/em\u3e (Thysanoptera: Thripidae), a Serious Pest of the Morris Arboretum Greenhouse Complex

Kosmopolis

https://repository.upenn.edu/cgi/viewcontent.cgi?article=1000&amp;context=morrisarboretum_internreports

Testing Biological Controls for \u3cem\u3eHeliothrips haemorrhoidalis\u3c/em\u3e (Thysanoptera: Thripidae), a Serious Pest of the Morris Arboretum Greenhouse Complex

Abstract

Similar works

Full text

Available Versions

ScholarlyCommons@Penn

Kosmopolis