scholarly journals Natural Parasitism of Phyllocnistis citrella (Lepidoptera: Gracillariidae) at Cuitlahuac, Veracruz, Mexico

1998 ◽  
Vol 81 (1) ◽  
pp. 30 ◽  
Author(s):  
Nestor Bautista-Martinez ◽  
Jose Luis Carrillo-Sanchez ◽  
Hiram Bravo-Mojica ◽  
Stephen D. Koch
ENTOMON ◽  
2020 ◽  
Vol 45 (3) ◽  
pp. 181-188
Author(s):  
T. Sharmitha ◽  
C. Gailce Leo Justin ◽  
S. Sheeba Joyce Roseleen ◽  
P. Yasodha

Three species of parasitoids viz., Telenomus dignus Gahan, Trichogramma japonicum, Ishii and Tetrastichus schoenobii Ferriere were recorded from the egg masses of rice yellow stem borer, Scirpophaga incertulas (Walker) in a field study. The extent of parasitism was high during Rabi (43.33 – 93.33 %) and low during Kharif (0 - 40.00 %). Parasitism by T. dignus was maximum in October (50.00 %), T. japonicum, in November (23.08 %) and T. schoenobii in February (55.55 %). dignus and T. schoenobii in combination parasitized maximum number of egg masses (41.82 %). Multiple parasitism by the three species was high in December (8.33 %) and January (7.14%). Parasitic potential was maximum, when T. schoenobii alone parasitised the egg masses followed by T. dignus and T. schoenobii in combination. Host density in the field influenced the extent of parasitism.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana P. G. S. Wengrat ◽  
Aloisio Coelho Junior ◽  
Jose R. P. Parra ◽  
Tamara A. Takahashi ◽  
Luis A. Foerster ◽  
...  

AbstractThe egg parasitoid Telenomus remus (Hymenoptera: Scelionidae) has been investigated for classical and applied biological control of noctuid pests, especially Spodoptera (Lepidoptera: Noctuidae) species. Although T. remus was introduced into Brazil over three decades ago for classical biological control of S. frugiperda, this wasp has not been recorded as established in corn or soybean crops. We used an integrative approach to identify T. remus, combining a taxonomic key based on the male genitalia with DNA barcoding, using a cytochrome c oxidase subunit I mitochondrial gene fragment. This is the first report of natural parasitism of T. remus on S. frugiperda and S. cosmioides eggs at two locations in Brazil. We also confirmed that the T. remus lineage in Brazil derives from a strain in Venezuela (originally from Papua New Guinea and introduced into the Americas, Africa, and Asia). The occurrence of T. remus parasitizing S. frugiperda and S. cosmioides eggs in field conditions, not associated with inundative releases, suggests that the species has managed to establish itself in the field in Brazil. This opens possibilities for future biological control programs, since T. remus shows good potential for mass rearing and egg parasitism of important agricultural pests such as Spodoptera species.


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1002
Author(s):  
María Gyomar Gonzalez-Gonzalez ◽  
Jose Blasco ◽  
Sergio Cubero ◽  
Patricia Chueca

Tetranychus urticae Koch is an important citrus pest that produces chlorotic spots on the leaves and scars on the fruit of affected trees. It is detected by visual inspection of the leaves. This work studies the potential of colour and hyperspectral imaging (400–1000 nm) under laboratory conditions as a fast and automatic method to detect the damage caused by this pest. The ability of a traditional vision system to differentiate this pest from others, such as Phyllocnistis citrella, and other leaf problems such as those caused by nutritional deficiencies, has been studied and compared with a more advanced hyperspectral system. To analyse the colour images, discriminant analysis has been used to classify the pixels as belonging to either a damaged or healthy leaves. In contrast, the hyperspectral images have been analysed using PLS DA. The rate of detection of the damage caused by T. urticae with colour images reached 92.5%, while leaves that did not present any damage were all correctly identified. Other problems such as damage by P. citrella were also correctly discriminated from T. urticae. Moreover, hyperspectral imaging allowed damage caused by T. urticae to be discriminated from healthy leaves and to distinguish between recent and mature leaves, which indicates whether it is a recent or an older infestation. Furthermore, good results were achieved in the discrimination between damage caused by T. urticae, P. citrella, and nutritional deficiencies.


2016 ◽  
Vol 82 (0) ◽  
Author(s):  
Leonardo Morais Turchen ◽  
Vanessa Golin ◽  
Bruna Magda Favetti ◽  
Alessandra Regina Butnariu ◽  
Valmir Antônio Costa

The neotropical stink brown bug, Euschistus heros (F.) (Hemiptera: Pentatomidae), is an insect pest to soybean crops in Mato Grosso State, Brazil. In this region, synthetic insecticides are frequently used for insect control. An alternative to the indiscriminate use of insecticides is the biological control with parasitoids. Thus, the objective of this study was to conduct the survey of parasitoids that use E. heros adults as hosts. Random samples were conducted during the harvests of 2009/10 and 2010/11 in two farms that produce soybean (conventional system) in Tangará da Serra, Mato Grosso State, Brazil. The total number of collected E. heros was: 297 (Field 1) and 293 (Field 2) in 2009/10 and 295 (Field 1) and 376 (Field 2) in 2010/11. Of these, 1.50 (Field 1) and 13.99% (Field 2) were parasitized in 2009/10 and 8.47 (Field 1) and 7.45% (Field 2) in 2010/11. The parasitoids found were Hexacladia smithii Ashmead (Hymenoptera: Encyrtidae) in both fields. This is the first record of parasitism in E. heros adults in the state of Mato Grosso, Brazil.


1987 ◽  
Vol 119 (3) ◽  
pp. 251-263 ◽  
Author(s):  
S.M. Smith ◽  
M. Hubbes ◽  
J.R. Carrow

AbstractDuring 1982 and 1984, ground releases of Trichogramma minutum Riley were assessed for control of the spruce budworm, Choristoneura fumiferana (Clemens), on 12- to 20-year-old, white spruce stands in northern Ontario. Maximum parasitism of susceptible egg masses was 16 and 87% following the release of 480 000 and 12 million female T. minutum per hectare, respectively. Releases at intervals of 1 week maintained parasitism of susceptible egg masses at constant levels throughout the oviposition period of spruce budworm. When parasitism of susceptible egg masses was maintained above 78.2% during the ovipositional period, total egg mass parasitism averaged 58.0% and resulted in an 80.3% reduction of overwintering 2nd-instar larvae. The optimal strategy for reducing spruce budworm was two releases of T. minutum at an interval of 1 week in the ovipositional period. This allowed a second generation of parasitoids to emerge from the spruce budworm eggs that were more efficient in maintaining high levels of parasitism than those emerging from the standard rearing host. Natural parasitism of spruce budworm egg masses was less than 4% and there was no carryover of parasitism in the years following inundative release. The rate of T. minutum release necessary to achieve effective mortality of spruce budworm during outbreak populations is discussed briefly.


2005 ◽  
Vol 95 (3) ◽  
pp. 305-310 ◽  
Author(s):  
Caroline Greve ◽  
Luiza Rodrigues Redaelli

A distribuição de imaturos de Phyllocnistis citrella Stainton, 1856 foi avaliada em folhas e em brotos de plantas de Citrus sinensis L. Osbeck var. Valência, no município de Montenegro (29°68'S e 51°46'W), Rio Grande do Sul, Brasil. A presença de ovos, lagartas e crisálidas (vivas e mortas) foi registrada nas folhas, em relação às superfícies abaxial e adaxial e à porção proximal, mediana e distal destas. As folhas que continham ovos, lagartas e/ou crisálidas foram classificadas e numeradas quanto à posição relativa a partir do ápice do broto e foram tomadas medidas no maior comprimento. Lagartas, crisálidas e ovos de P. citrella evidenciaram padrão de distribuição agregado tanto no nível de brotos quanto no de folhas. O comprimento médio das folhas onde ocorreram as pupas era maior do que aquele onde se encontravam as lagartas. Os ovos foram registrados em maior proporção no terço mediano das folhas, em ambas superfícies, já as lagartas e crisálidas ocorreram com mais freqüência nos terços mediano e proximal das folhas.


1997 ◽  
Vol 122 (6) ◽  
pp. 829-836 ◽  
Author(s):  
D.S. Achor ◽  
H. Browning ◽  
L.G. Albrigo

Young expanding leaves of `Ambersweet' [Citrus reticulata Blanco × C. paradisi Macf. × C. reticulata) × C. sinensis (L) Osb.] with feeding injury by third larval stage of citrus leafminer (Phyllocnistis citrella) were examined by light and electron microscopy for extent of injury and tissue recovery over time. Results confirmed that injury is confined to the epidermal layer, leaving a thin covering over the mine tunnel that consisted of the cuticle and outer cell wall. Wound recovery consisted of two possible responses: the production of callus tissue or the formation of wound periderm. The production of callus tissue developed within 3 days of injury when the uninjured palisade or spongy parenchyma below the injured epidermis produced callus tissue through periclinal or diagonal cell divisions. After 1 month, the entire epidermis was replaced by callus tissue. In the absence of secondary microbial invasion, this callus tissue developed a thick cuticle, followed by development of a covering of platelet wax after 4 months. Alternatively, wound periderm formed if the outer cuticular covering was torn before the cuticle had developed sufficiently to prevent the exposed cells from being desiccated or invaded by fungi, bacteria, or other insects. The wound periderm consisted of a lignified layer of collapsed callus cells, a suberized phellem layer, and a multilayered phelloderm-phellogen. Since there were always cellular collapse or fungi and bacteria associated with wound periderm formation, it was determined to be a secondary effect, not a direct effect of leafminer feeding.


2015 ◽  
Vol 8 (4) ◽  
pp. 371-374 ◽  
Author(s):  
Sanghyeob Lee ◽  
Il-Kwon Kim ◽  
Young-Kyu Park ◽  
Chung-Won Choi ◽  
Bong-Kyu Byun

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