scholarly journals Comparing Exogenous Methods to Induce Plant-Resistance Against a Bark-Feeding Insect

2021 ◽  
Vol 12 ◽  
Author(s):  
Yayuan Chen ◽  
Adriana Puentes ◽  
Christer Björkman ◽  
Agnès Brosset ◽  
Helena Bylund
Keyword(s):  
Plant Defenses ◽  
Plant Protection ◽  
Insect Herbivory ◽  
Mechanical Damage ◽  
The Other ◽  
Early Exposure ◽  
Protection Measure ◽  
Seedling Resistance ◽  
Pine Weevil ◽  
Late Exposure

Exogenous application of the plant hormone methyl jasmonate (MeJA) can trigger induced plant defenses against herbivores, and has been shown to provide protection against insect herbivory in conifer seedlings. Other methods, such as mechanical damage to seedlings, can also induce plant defenses, yet few have been compared to MeJA and most studies lack subsequent herbivory feeding tests. We conducted two lab experiments to: (1) compare the efficacy of MeJA to mechanical damage treatments that could also induce seedling resistance, (2) examine if subsequent insect damage differs depending on the time since induction treatments occurred, and (3) assess if these induction methods affect plant growth. We compared Scots pine (Pinus sylvestris) seedlings sprayed with MeJA (10 or 15 mM) to seedlings subjected to four different mechanical bark damage treatments (two different bark wound sizes, needle-piercing damage, root damage) and previous pine weevil (Hylobius abietis) damage as a reference treatment. The seedlings were exposed to pine weevils 12 or 32 days after treatments (early and late exposure, hereafter), and resistance was measured as the amount of damage received by plants. At early exposure, seedlings treated with needle-piercing damage received significantly more subsequent pine weevil feeding damage than those treated with MeJA. Seedlings treated with MeJA and needle-piercing damage received 84% less and 250% more pine weevil feeding, respectively, relative to control seedlings. The other treatments did not differ statistically from control or MeJA in terms of subsequent pine weevil damage. For the late exposure group, plants in all induction treatments tended to receive less pine weevil feeding (yet this was not statistically significant) compared to control seedlings. On the other hand, MeJA significantly slowed down seedling growth relative to control and all other induction treatments. Overall, the mechanical damage treatments appeared to have no or variable effects on seedling resistance. One of the treatments, needle-piercing damage, actually increased pine weevil feeding at early exposure. These results therefore suggest that mechanical damage shows little potential as a plant protection measure to reduce feeding by a bark-chewing insect.

scholarly journals Insect herbivory facilitates the establishment of an invasive plant pathogen

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martin M. Gossner ◽  
Ludwig Beenken ◽  
Kirstin Arend ◽  
Dominik Begerow ◽  
Derek Peršoh
Keyword(s):  
Invasive Plant ◽  
Pathogenic Fungus ◽  
Feeding Activity ◽  
Insect Herbivory ◽  
Forest Health ◽  
Mechanical Damage ◽  
Pathogenic Fungi ◽  
Fungal Colonization ◽  
Feeding Damage ◽  
The Impact

AbstractPlants can be severely affected by insect herbivores and phytopathogenic fungi, but interactions between these plant antagonists are poorly understood. We analysed the impact of feeding damage by the abundant herbivore Orchestes fagi on infection rates of beech (Fagus sylvatica) leaves with Petrakia liobae, an invasive plant pathogenic fungus. The fungus was not detected in hibernating beetles, indicating that O. fagi does not serve as vector for P. liobae, at least not between growing seasons. Abundance of the fungus in beech leaves increased with feeding damage of the beetle and this relationship was stronger for sun-exposed than for shaded leaves. A laboratory experiment revealed sun-exposed leaves to have thicker cell walls and to be more resistant to pathogen infection than shaded leaves. Mechanical damage significantly increased frequency and size of necroses in the sun, but not in shade leaves. Our findings indicate that feeding damage of adult beetles provides entry ports for fungal colonization by removal of physical barriers and thus promotes infection success by pathogenic fungi. Feeding activity by larvae probably provides additional nutrient sources or eases access to substrates for the necrotrophic fungus. Our study exemplifies that invasive pathogens may benefit from herbivore activity, which may challenge forest health in light of climate change.

THE INHERITANCE OF LEAF RUST RESISTANCE IN SEVEN VARIETIES OF COMMON WHEAT

1961 ◽  
Vol 41 (2) ◽  
pp. 342-359 ◽  
Author(s):  
R. G. Anderson
Keyword(s):  
Leaf Rust ◽  
Common Wheat ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Susceptible Variety ◽  
The Other ◽  
Seedling Resistance ◽  
Genetic Studies ◽  
Type Reaction ◽  
Biological Studies

The inheritance of seedling resistance to races 1a, 5a, 11, 15a and 126a of leaf rust was studied in the varieties Exchange and Selkirk and to races 1a and 15a in the varieties Lee, Gabo, Timstein, Mayo 52 and Mayo 54. Thatcher was used as the susceptible variety. Rust tests were carried out on F1 and F2 populations of diallel crosses among these varieties and on F2 families from the backcrosses to Thatcher. Two genes were found. One gene LrE conditions a (2) type reaction to all five races in Exchange and Selkirk. The other gene LrL conditions a (; 1 =) type reaction to races 1a and 15a in all seven varieties. Isogenic lines possessing these genes are being developed in the varieties Prelude and Thatcher. The importance of such lines in future genetic studies and their application in other biological studies are discussed.The increase in amount of leaf rust found on Lee and Selkirk in Canada during the period 1951–1958 is accounted for by the increase of races which render the gene LrL ineffective in these two varieties.

scholarly journals Impact induced mechanical damage of Agria potato tubers

2012 ◽  
Vol 51 (No. 2) ◽  
pp. 39-43 ◽  
Author(s):  
J. Blahovec
Keyword(s):  
Potato Variety ◽  
Impact Test ◽  
Mechanical Damage ◽  
The Other ◽  
Pig Slurry ◽  
Potato Tubers ◽  
Irrigation Regimes ◽  
Other Hand ◽  
Flat Side

Potato variety Agria was cultivated in different fertilisation and/or irrigation regimes. Tuber damage after impact was studied two months after the harvest with aim to find some relation between the regime of cultivation and impact test tuber damage. It was found that tuber cracking and/or crushing belongs to the most frequent mechanisms of damage masking usual bruising in many cases. Most severe tuber cracking was observed for cultivation with irrigation and classical methods of fertilisation. On the other hand, bruising was most frequent in case without any irrigation and fertilisation and in cases used for fertilisation the pig slurry. In every cultivation regime the bruising was more pronounced in narrower tuber side in comparison to the wider flat side.

scholarly journals Efficacy and speed of action of selected plant protection products on Lymantria dispar in laboratory conditions

2017 ◽  
Vol 18 ◽  
pp. 62 ◽  
Author(s):  
Z.D. Zartaloudis ◽  
M.D. Kalapanida ◽  
E.I. Navrozidis
Keyword(s):  
Bacillus Thuringiensis ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Plant Protection ◽  
Plant Protection Products ◽  
The Other ◽  
Larval Instars ◽  
Laboratory Conditions ◽  
Bacillus Thuringiensis Subsp

In this study some selected insecticides were evaluated for their effect on gypsy moth Lymantria dispar L., (Lepidoptera: Lymantriidae) under laboratory conditions. Diflubenzuron, methoxyfenozide, triflumuron, fenoxycarb, fenoxycarb + lufenuron, Bacillus thuringiensis 50% subsp. kurstaki + Bacillus thuringiensis 50% subsp. aizawai, Bacillus thuringiensis subsp. aizawai and spinosad were used in the recommended concentration, against the 1st, 2nd, 3rd and 4th larval instars of L. dispar. The effectiveness of the above insecticides as well as the speed of action (LTime50 and LTime90) expressed in days, were examined in detail. Spinosad and methoxyfenozide presents a relatively higher speed of action in relation to the other insecticides. LTime50 of spinosad and methoxyfenozide did not differ significantly among the first three larval instars and ranged from 0 to 0.61 and 1.13 to 1.74 days, respectively. Regarding IGRs, the mixture (fenoxycarb + lufenuron) and triflumuron were the most effective in relation to the other IGRs tested. Moreover, Bacillus thuringiensis toxins were effective only against the first two larval instars.

scholarly journals SUSCEPTIBILITY OF LEMON BALM (Melissa officinalis L.) VARIETIES TO SEPTORIA LEAF SPOT (Septoria melissae Desm.) IN HUNGARY

2019 ◽  
Vol 18 (1) ◽  
pp. 47-56
Author(s):  
Gergő Kovács ◽  
Éva Zámbori-Németh ◽  
Géza Nagy
Keyword(s):  
Leaf Spot ◽  
Plant Protection ◽  
Disease Incidence ◽  
Weather Conditions ◽  
The Other ◽  
Melissa Officinalis ◽  
Lemon Balm ◽  
Protection Method ◽  
Cultivated Plant ◽  
Septoria Leaf Spot

Lemon balm (Melissa officinalis L.) is a widely cultivated plant in Europe. Septoria melissae Desm. is the most important pathogen of lemon balm crops, which may cause serious yield loss by the severe leaf fall. As chemical control of the pathogen is restricted, alternative plant protection methods, like the use of tolerant varieties, should be taken under consideration. The goal of our work was to evaluate the susceptibility of three lemon balm varieties to Septoria leaf spot in field. The trials were carried out in 2016 and 2017 in Budapest-Soroksár, Hungary. Dynamics of infection showed characteristic sharp increase from the beginning of August in both years. The lowest infection levels were observed in cultivar ‘Lemona’. The disease incidence in the middle of August was 19% in the first year and 59% in the second year, while these values were over 40% and 70% in the other cultivars ‘Soroksári’ and ‘Quedlinburger Niederliegende’, respectively. The manifestation of symptomps was also significantly lighter on the ‘Lemona’ plants and they had the highest ratio of healthy leaves (81%) compared to the other cultivars. According to the data, weather conditions might modify the range of the differences among the cultivars. It was concluded that appropriate selection of varieties could be an effective and enviromental friendly plant protection method in the practice of lemon balm cultivation.

scholarly journals Environmental function and control of heno motita (Tillandsia recurvata) in the atmospheric basin of Tula de Allende Hidalgo

2021 ◽  
pp. 19-30
Author(s):  
Marisol RESÉNDIZ-VEGA ◽  
Gabriela SÁNCHEZ-TRUJILLO
Keyword(s):  
Heavy Metals ◽  
Acetic Acid ◽  
Sodium Bicarbonate ◽  
Mechanical Damage ◽  
Management Program ◽  
The Other ◽  
Environmental Function ◽  
And Control ◽  
Allelopathic Substance ◽  
Specific Management

The purpose of this article is to make a proposal for the control of heno motita (Tillandsia recurvata), based on the analysis of its environmental function within the atmospheric basin of Tula, to contribute to the solution of a state forest problem. Its approach is quantitative experimental since it seeks to explain how the application of 5% acetic acid and 80g / l sodium bicarbonate affects the emergence of new shoots and the Hay Motita plant directly, as well as to identify the function that said plant fulfills. within the microenvironment. The findings show that heno motita is a plant that seeks a support to capture nutrients from the air, however, shading causes the host plant to decrease its efficiency in capturing energy, likewise there is mechanical damage due to its weight and a chemical one since it secretes an allelopathic substance that damages the new shoots. On the other hand, Tillandsia recurvata "sequesters" particles of different materials such as heavy metals in its trichomes, thus contributing to the sanitation of the atmosphere. Finally, the steps to follow to develop a specific management program are proposed.

ROLE OF GRAM PANCHAYAT IN HANDLING POST-COVID MEASURES IN INDIA: AN EVALUATIVE STUDY

2021 ◽  
pp. 30-32
Author(s):  
Parvez Shahid Ali
Keyword(s):  
Rural Areas ◽  
Rural Population ◽  
Well Being ◽  
The Self ◽  
The Other ◽  
Protection Measure ◽  
Rural People ◽  
Evaluative Study ◽  
Deadly Disease

Dealing with globally spread Covid-19 pandemic in 2020-2021 is a big issue for India, like most of the other countries of this world. Restrictions of lockdown have shattered various sections of our country. These sections need national attention with top priority to bring back normalcy. In this area, protecting health and livelihood of rural areas come as signicant parts in a Covid protection measure. Here, we should particularly mention the role of Gram Panchayat without whom, this task would certainly be difcult to handle. Rural areas of India are still very backward if we compare them with our urbanized zones. In those remote villages, Gram Panchayat is the self-governance body that is functional to maintain safety and well-being of the rural people. Our Government has launched a number of arrangements and schemes in current years providing Gram Panchayat surplus and improved support for handling rural issues. In a crucial time as this Covid-19 pandemic, such initiatives and even more should be sanctioned for our Gram Panchayats boosting their efciency to keep safe our rural population, make them properly aware about the deadly disease as well as ensure provisions and security to stabilize them. Issues, such as, migrant villagers and supporting their dropped economy are something that become their additional responsibilities. In our Evaluative Study, we have found exclusive methods in which our Gram Panchayats have worked to support all the above stated problems. We have identied certain innovative approaches applied as post-covid preventions measures in rural areas that can be further enhanced to deal similar crisis.

scholarly journals Risk Assessment of the Plant Protection Product PROMAN – with the Active Ingredient Metobromuron

2019 ◽  
pp. 56-58
Author(s):  
Marit Låg ◽  
Hubert Dirven ◽  
Jan Ludvig Lyche ◽  
Asbjørn Magne Nilsen ◽  
Katrine Borgå ◽  
...  
Keyword(s):  
Plant Protection ◽  
Developmental Toxicity ◽  
Plant Protection Products ◽  
The Other ◽  
Carcinogenicity Study ◽  
Developmental Effects ◽  
Different Types ◽  
Carcinogenic Effects ◽  
Androgenic Effect ◽  
Leydig Cell Tumours

Proman is a new product containing the active substance metobromuron. The intended use is as a broad spectrum selective herbicide for potatoes grown outdoors. VKM’s Panel on Plant Protection Products has discussed the questions raised by The Norwegian Food Safety Authority in the Terms of reference and has stated the following opinion: On the relevance of the carcinogenic effects observed in the rat carcinogenicity study; fibrosarcomas in females and pheochromocytomas and Leydig cell tumours in males: It is the opinion of VKM’s Panel for Plant Protection Products that the relevance of the observed incidence in mammary gland tumours and Leydig cell tumours in the rat carcinogenicity study is strengthened by the fact that the tumours are observed in hormone responsive tissues. The panel concludes that the carcinogenic effects observed in the rat carcinogenicity study are likely to be relevant for tumours that are influenced by the endocrine system, also in humans. On the higher incidences of still dumbbell-shaped centres of thoracic vertebrae and nonossification of the 13th rib observed in the rat developmental toxicity study and whether these are considered to be malformations: VKM’s Panel on Plant Protection Products has discussed the classification of the different types of incomplete ossifications and concluded that incomplete ossification of sternebrae and non-ossification of the 13th rib in rats should by itself be considered to be variations, and not adverse developmental effects. On the other hand, the Panel agrees with ECHA that the “thoracic vertebral centres still dumbbell-shaped” should be considered as malformations, due to limited data and understanding of the mechanism underlying the observed slow reversal of these anomalies. Furthermore, it is the view of the Panel that the different types of retarded ossification induced by the exposure of metobromuron should be considered as a whole when assessing for developmental effects. On the establishment of the NOAEL for the developmental toxicity study in rats and the reference value (ARfD): VKM’s Panel on Plant Protection Products supports the proposal of an ADI value of 0.008 mg/kg bw/day based on a NOAEL of 0.8 mg/kg bw/day from the 2-year study in mouse, and VKM Report 2015: 03 5. AOEL of 0.016 mg/kg bw/day based on the NOAEL of 1.6 mg/kg bw/day from the 1-year feeding study in dog. An UF of 100 is applied. The panel suggests on the other hand an ARfD of 0.03 mg/kg bw based on a LOAEL of 10 mg/kg bw /day with the observations of incomplete ossification in the rat developmental study. An UF of 300 is applied. On the possible anti-androgenic potential of metobromuron: It is the view of the Panel that the rat carcinogenicity study suggests that metobromuron may possess endocrine disrupting potency. The data from the Hershberger in vivo rat study and the in vitro studies is also suggestive of a weak anti-androgenic effect. Thus, it is the opinion of the VKM Panel on Plant Protection Products that an anti-androgenic effect of metobromuron cannot be excluded.

scholarly journals The Impact of Insect Herbivory in the Level of Cannabinoids in CBD Hemp Varieties

2021 ◽  
Author(s):  
Brandon Jackson ◽  
Lenneisha Gilbert ◽  
Tigist Tolosa ◽  
Shellyann Henry ◽  
Victoria Volkis ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Cannabis Sativa ◽  
Insect Herbivory ◽  
Mechanical Damage ◽  
Dry Weight ◽  
The United States ◽  
Corn Earworm ◽  
Herbivore Damage ◽  
And Control ◽  
The Impact

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.

Plant Defenses Against Insect Herbivory

2010 ◽  
pp. 189-208 ◽  
Author(s):  
Farha-Rehman ◽  
Fareed A. Khan ◽  
Shoeba B. Anis ◽  
S. M. A. Badruddin
Keyword(s):  
Plant Defenses ◽  
Insect Herbivory
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