scholarly journals Pest Management Needs and Limitations for Corn Earworm (Lepidoptera: Noctuidae), an Emergent Key Pest of Hemp in the United States

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kadie E Britt ◽  
Thomas P Kuhar ◽  
Whitney Cranshaw ◽  
Christopher T McCullough ◽  
Sally V Taylor ◽  
...  

Abstract Corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), has emerged as an injurious insect pest to hemp, Cannabis sativa L., a crop newly reintroduced to the United States. Growing hemp presents a potential alternative economic opportunity for farmers but can be challenging with a market that is unstable and just developing. One of the most notable production challenges is managing corn earworm, an insect pest that is particularly damaging when it feeds on flower buds produced in cannabinoid varieties, creating extensive bud tunneling and wounds that allow entry of pathogens that can aid development and presence of bud rot. Damage to seeds is of lesser concern in hemp cultivars grown for grain and minimal risk is associated with hemp grown for fiber. Our ability to research hemp has only recently been allowed as production was largely suspended following World War II and, as such, there has been limited opportunity to develop information for empirically-based pest management recommendations. Further complicating development of integrated pest management (IPM) strategies are regulatory challenges associated with providing registration support to add hemp to pesticide labels, as it was not formally recognized as a crop by U.S. regulatory agencies until late 2019. Research needs and challenges to develop effective IPM programs for corn earworm on hemp are discussed here.

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Whitney Cranshaw ◽  
Melissa Schreiner ◽  
Kadie Britt ◽  
Thomas P Kuhar ◽  
John McPartland ◽  
...  

Abstract Hemp (Cannabis sativa L.) is now being grown within the United States over a much broader geographic area and for different uses than during its last period of significant production that ended after World War II. Within the past 3 yr, a large number of arthropod species have been documented to feed on hemp in the United States. Among key pest species, corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), has demonstrated greatest potential for crop injury, being particularly damaging to flower buds. Hemp russet mite, Aculops cannibicola (Farkas), and cannabis aphid, Phorodon cannabis Passerini, are the two species observed most damaging among those that suck plant fluids. Eurasian hemp borer, Grapholita delineana Walker, is widely present east of the Rocky Mountains and appears to have potential to significantly damage both flower buds and developing seeds. Numerous species of caterpillars, grasshoppers, and beetles chew hemp foliage; the severity of these defoliation injuries appears to be minimal, but needs further study. Similarly, numerous seed feeding hemipterans, most notably stink bugs and Lygus bugs, are regularly found in the crop but injury potential remains unclear. Some preliminary efforts have been made to develop integrated pest management strategies for these insects, particularly for corn earworm. Future research can be expected to rapidly resolve many of the data gaps that presently restrict advancing pest management on the crop. However, a major confounding issue involves the use of pesticides on hemp. Federal agencies have not yet provided clear direction on this issue, and regulatory decisions have subsequently devolved to the states.


Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 940
Author(s):  
Olufemi S. Ajayi ◽  
Michelle Samuel-Foo

There has been a resurgence in the cultivation of industrial hemp, Cannabis sativa L., in the United States since its recent legalization. This may facilitate increased populations of arthropods associated with the plant. Hemp pests target highly marketable parts of the plant, such as flowers, stalks, and leaves, which ultimately results in a decline in the quality. Industrial hemp can be used for several purposes including production of fiber, grain, and cannabidiol. Thus, proper management of pests is essential to achieve a substantial yield of hemp in the face of climate change. In this review, we provide updates on various arthropods associated with industrial hemp in the United States and examine the potential impact of climate change on corn earworm (CEW) Helicoverpa zea Boddie, a major hemp pest. For example, temperature and photoperiod affect the development and diapause process in CEW. Additionally, drought can lead to a reduction in hemp growth. Host plant diversity of CEW may prevent populations of the pest from reaching outbreak levels. It is suggested that hemp varieties resistant to drought, high soil salinity, cold, heat, humidity, and common pests and diseases should be selected. Ongoing research on effective management of CEW in hemp is critical.


2009 ◽  
Vol 20 (6) ◽  
pp. 279-284 ◽  
Author(s):  
Frank H. Arthur ◽  
Judy A. Johnson ◽  
Lisa G. Neven ◽  
Guy J. Hallman ◽  
Peter A. Follett

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1450
Author(s):  
Mariane Coelho ◽  
Donald R. Cook ◽  
Angus L. Catchot ◽  
Jeff Gore ◽  
André L. Lourenção ◽  
...  

Soybean is considered one of the most valuable crops in the United States of America. Helicoverpa zea (Boddie) is among several insect pests which are associated with soybean, damaging leaves when infestations occur during the vegetative stages, and flowers and pods during the reproductive stages, which can directly impact yield. Artificial fruit removal is a method used to understand insect damage and to adjust action levels for control. The objective of this work was to evaluate the impact of five levels of fruit removal (0%, 25%, 50%, 75% and 100%) at four stages (R2, R3, R4 and R5) on maturity and yield of soybean. These methods were used to simulate H. zea damage under controlled conditions in non-irrigated environments, during 2016 and 2017. There was a significant interaction between fruit removal timing and fruit removal level for the percentage of non-senesced main stems and abscised leaves. For soybean yield, there was no significant interaction between fruit removal timing and fruit removal level. Plots that received fruit removal treatments at R5 had significantly lower soybean yields compared to plots that received damage at other growth stages and the nontreated control. Plots with 100% fruit removal had significantly lower yields compared to plots that received any of the other fruit removal treatments. These data demonstrate that indeterminate midmaturity group IV soybeans that are commonly grown in the midsouthern region of the United States may be able to compensate for even severe levels of fruit loss early during the reproductive portion of the growing season if favorable growing conditions occur.


2021 ◽  
Author(s):  
Brandon Jackson ◽  
Lenneisha Gilbert ◽  
Tigist Tolosa ◽  
Shellyann Henry ◽  
Victoria Volkis ◽  
...  

Abstract Background In the United States, industrial hemp is defined as a Cannabis sativa L. plant not containing more than 0.3% delta-9-tetrahydrocannabinol (D9THC) by dry weight. Plants respond to insect herbivore damage by changing their chemistry to counter the effects of herbivore attack. Here, we hypothesized that the corn earworm (Helicoverpa zea) infestation might impact the level of cannabinoids (Cannabidiol (CBD) and D9THC). Results In a laboratory trial, the CBD hemp, Cherry Blossom, and The Wife varieties were subjected to herbivore damage (HD), Mechanical damage (MD), and Control. After 24hrs of the treatments, we found a significant increase in CBD and D9THC in HD plants compared with MD and Control plants. Similar experiments were conducted in the field condition. A substantial increase in CBD and D9THC observed in herbivore damaged hemp plants compared to the control plants. However, in the field trial, the levels of cannabinoids were not significantly higher in The wife variety. Interestingly, the Corn earworm larvae fed with CBD and D9THC spiked diet showed a significant reduction in body mass, as compared to the larvae fed with the control diets.ConclusionsThe level of cannabinoids seems not genetically fixed somewhat; it is affected by insect herbivory. Our results suggest that CBD hemp plants are exposed to insect herbivory spikes in cannabinoid production and surpass the 0.3 % legal limit of D9THC. The growth and development of Corn earworm, the number one hemp pest in North America affected by cannabinoids. The increased concentration of CBD and D9THC observed in herbivore damaged hemp plants might be associated with the direct deterrence of the corn earworm larvae. Further research underway using different hemp varieties to assess if herbivory and other biotic stressors impact the level of cannabinoids.


2019 ◽  
Vol 112 (4) ◽  
pp. 1845-1857 ◽  
Author(s):  
Tom R Bilbo ◽  
Francis P F Reay-Jones ◽  
Dominic D Reisig ◽  
Jeremy K Greene

Abstract The corn earworm, Helicoverpa zea (Boddie), is managed in corn and cotton in the United States primarily using transgenic cultivars that produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). However, increasing reports of resistance to one or more Bt proteins threaten the continued efficacy of Bt traits. To better understand the development of resistance of H. zea to Bt corn and cotton in the southeastern United States, we monitored for resistance to Cry1A.105 and Cry2Ab2 among 22 field populations of H. zea collected in non-Bt and Bt corn expressing Cry1A.105 + Cry2Ab2 during 2017 and 2018. Colonies were established in the laboratory and progeny were screened in diet-overlay bioassays to purified Cry1A.105 and Cry2Ab2 proteins. Compared with two susceptible laboratory colonies, all 14 field colonies tested with Cry1A.105 were highly resistant, with resistance ratios (RRs) ranging from 13.5 to >4,000. For Cry2Ab2, 19 colonies were tested and RRs ranged from 0.26 to 33.7. Field populations were significantly more susceptible to Cry2Ab2 than Cry1A.105. We documented variability in F0 and F1 pupal weight and developmental rates of natural populations of H. zea, but observed no significant correlation with susceptibility to either Cry1A.105 or Cry2Ab2. Our results expand on the recent reports of H. zea resistance to Cry1A and Cry2A proteins and will aid in the design and deployment of future pyramided crops in the United States.


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