PHENOLOGY OF HOPLOCAMPA MONTANICOLA ROHWER (TENTHREDINIDAE) AND ANTHONOMUS QUADRIGIBBUS SAY (CURCULIONIDAE) ON THEIR HOST PLANT AMELANCHIER ALNIFOLIA NUTT. (ROSACEAE) IN SASKATCHEWAN

1990 ◽  
Vol 122 (5) ◽  
pp. 901-906 ◽  
Author(s):  
R.G. St. Pierre ◽  
D.M. Lehmkuhl

AbstractAdult Hoplocampa montanicola Rohwer emerged in mid-May, 6.2 ± 3.2 days (mean ± SE) prior to the period of peak anthesis in Amelanchier alnifolia Nuttall. Oviposition, one egg per flower, occurred during the period of petal drop in late-May; a mean ± SE of 2.2 ± 0.2 eggs were deposited in each inflorescence. Eggs hatched 7.7 ± 3 days (mean ± SE) after the period of primary petal drop and larvae fed on a mean ± SE of 1.8 ± 0.14 fruit per infructescence. Larvae completed development by the end of June, just as the first fruit of A. alnifolia were beginning to ripen. Larvae overwintered in the leaf litter.Adult Anthonomus quadrigibbus Say (previously assigned to the genus Tachypterellus) were first collected in mid- to late-May during the periods of anthesis and fruit drop in A. alnifolia. Immature fruit fed upon were often extensively damaged. Oviposition occurred toward the end of fruit drop in A. alnifolia, 30.6 ± 2.5 days (mean ± SE) after the period of peak anthesis. Only one egg was laid in a puncture at the base of a fruit. Larval feeding was restricted to ovules and occurred in fruit retained on the plant. Pupation and adult emergence occurred in mid-July as fruit were ripening. The new generation of adults then entered the leaf litter to overwinter.

2018 ◽  
Vol 8 (3) ◽  
pp. 43-51
Author(s):  
ETHAN PEREGRINE BEAVER ◽  
JOHN GREHAN

It is difficult to associate species of the wood-boring moth in the genus Aenetus with their host plant, because larvae develop inside live trees. A new method is described for rearing larvae of Aenetus eximia, A. lewinii, A. blackburnii, A. ligniveren and A. scotti in cut stems of trees containing larval tunnels by feeding them apple pieces. Larvae that completed development were reared from 49 to 396 days after collection from the field. Aspects of larval feeding webs and adult emergence are described, and new host records are documented. The rearing method is shown to provide an effective means of accurately determining the species of Aenetus developing inside a given host plant.  It was more convenient than obtaining pupae or emerging adults in the field, which is often not possible to do. The method should be useful for conducting surveys, particularly for species with wide distribution ranges. This method may also be effective for the study of other genera of callus feeding, stem boring Hepialidae, such as Archaeoaenetus, Endoclita, Phassus, Schausiana and Zeloptypia.


2002 ◽  
Vol 20 (3) ◽  
pp. 138-142
Author(s):  
William E. Klingeman

Abstract The bagworm (Thyridopteryx ephemeraeformis (Haworth)) is a polyphagous, native pest of numerous deciduous and evergreen ornamental plants. Bagworm larvae were used to investigate host plant susceptibility among ten species and cultivars of maples that are economically important and commonly encountered in landscapes in the eastern United States. Data analyses from 48-hour choice assays, conducted in the laboratory during 2000 and 2001, indicated that differences existed among maples for bagworm feeding preferences and host plant susceptibility. Results from the 48-hour trials were not as accurate as seasonal no-choice assays, however. No-choice assays during both seasons quantified resistance among maples that limited larval bagworm survival and development. Measurements of larval feeding injury demonstrated resistance in paperbark maple (Acer griseum (Franch.) Pax) and trident maple (A. buergerianum Miq.) when compared with other maples. Laboratory results were corroborated during 2001 by a no-choice field assay, in which early instar bagworm larvae performed well on the majority of maples. In contrast, paperbark maple and trident maple were resistant to bagworm feeding, while ‘Autumn Blaze’ Freeman maple (A. x freemanii E. Murray), a hybrid cross obtained by breeding A. rubrum with A. saccharinum, showed moderate resistance.


2006 ◽  
Vol 96 (2) ◽  
pp. 205-212 ◽  
Author(s):  
J. Moreau ◽  
B. Benrey ◽  
D. Thiéry

AbstractFor insect herbivores, the quality of the larval host plant is a key determinant of fitness. Therefore, insect populations are supposed to be positively correlated with the nutritional quality of their host plant. This study aimed to determine if and how different varieties of grapes (including the wild grape Lambrusque) affect both larval and adult performance of the polyphagous European grapevine moth Lobesia botrana (Denis & Schiffermüller). Significant differences were found in larval development time, but not in pupal mass, adult emergence rate, or sex ratio. Although the fecundity of females is not different among varieties, females fed on some varieties produced eggs of different sizes which are correlated to their fertility. Thus, females adapt resource allocation to eggs depending on their diet as larvae. Using a fitness index, the average reproductive output was found to be highest for females reared on cv. Chardonnay. Females reared on wild grape produced a fitness index identical to the cultivated grapes. However, Lambrusque and Gewurztraminer separate themselves from the cultivated varieties according to our discriminant analyses. It is emphasized, through this study, that cultivars fed on by larvae should be considered in the population dynamics of L. botrana and that egg number is insufficient to determine host plant quality.


1986 ◽  
Vol 118 (4) ◽  
pp. 351-359 ◽  
Author(s):  
M.T. AliNiazee

AbstractSeasonal history, adult flight activity, and damage of the obliquebanded leafroller, Choristoneura rosaceana (Harris), on filbert were studied during a 7-year period between 1976 and 1984. Data from periodic field counts and moth catches in sex-attractant traps indicated two generations per year. The first-generation adult capture peak was generally higher than the second, except in 1978 when about an equal number of moths were trapped from both generations. A physiological time scale, using degree-days (DD), was devised for predicting emergence of obliquebanded leafroller adults. The first adults from overwintering larvae emerged at approximately 374 DD above a threshold of 10 °C starting 1 March. A total of 1172 DD were required between the first and the last adult emergence during the first generation and about 519 DD during the second generation. The obliquebanded leafroller causes both foliar and nut damage in filbert orchards of Oregon. Foliar damage was insignificant, but nut damage, caused exclusively by the first-generation larvae during June and early July, was highly destructive. Larval feeding on nuts caused staining and premature drop of infested nuts resulting in substantial yield reduction in heavily infested orchards.


2019 ◽  
Vol 151 (04) ◽  
pp. 475-497 ◽  
Author(s):  
M. Javahery

AbstractThe natural history of Corythucha juglandis (Fitch) and Gargaphia tiliae (Walsh) (Hemiptera: Tingidae) was studied in Ontario and Québec, Canada. These univoltine species overwinter as adults in leaf litter in a state of reproductive diapause and become active in April or May. They are specific to their host plants. Adults, eggs, and nymphs of both species were collected from the underside of leaves of host plants. The reproductive systems of both male and female, as well as eggs, nymphs, and operculum of the eggs of the two species, are described and illustrated. Fecundity, incubation period, development of nymphs, feeding, mating, and oviposition were studied. Mating was end-to-end at an angle of 35–40°. The reproductive potential, oviposition pattern, and site selection in the two species were investigated. Parental care of eggs and brood of G. tiliae is also reported and illustrated. Ocelli, true spermathecae, true egg micropyles, and true egg burster are absent in the two species. Fertilisation takes place before chorion formation. Adults, nymphs, and new generation aggregate on the underside of leaves of their host or nearby deciduous plants. In October they fly a short distance to overwintering sites within leaf litter.


2005 ◽  
Vol 85 (4) ◽  
pp. 949-954 ◽  
Author(s):  
C. C. Knight ◽  
K. P. Pauls ◽  
M. K. Sears ◽  
A. W. Schaafsma

Western corn rootworm (WCR), Diabrotica virgifera virgifera L., is the most serious insect pest of corn, Zea mays L., in North America. Crop rotation had successfully controlled this pest until the late 1980s when a new biotype that lays its eggs in non-corn crops was discovered in Illinois. This biotype has spread to parts of Indiana, Michigan, and Ohio, and threatens Ontario. By using emergence cages, Pherocon Am® sticky traps and corn root ratings, egg-laying behaviour of WCR in Ontario was assessed in strip crop settings that represent typical cropping systems of southern Ontario. WCR adults were active in both soybean and winter wheat fields in July and August. Larval feeding and adult emergence in first-year corn fields following soybean and wheat were similar, confirming that oviposition did occur in both crops. These data do not, however, provide conclusive evidence for the presence of the rotation resistant WCR in Ontario because previous studies have demonstrated that WCR are capable of utilizing other crops for oviposition. Key words: Western corn rootworm, Diabrotica virgifera virgifera, strip plots, corn, soybean, wheat (winter)


1999 ◽  
Vol 131 (6) ◽  
pp. 729-742 ◽  
Author(s):  
Christopher Asaro ◽  
Douglas C. Allen

AbstractThe life history of pine false webworm, Acantholyda erythrocephala (L.), in three pine (Pinaceae) plantations in northern New York is similar to that reported for this species on red pine, Pinus resinosa Aiton, in Ontario. Adult emergence extended from early May to early June. The sex ratio of emerging adults favored males by as much as 2.7:1. Oviposition occurred from mid-May to early June. Significantly more eggs per fascicle were deposited on the distal third of branches and in the lower third of the crown. Larval feeding took place throughout June. The proportion of prepupae remaining in the soil for more than 1 year varied from 9% to 66% between two sites. There was no evidence of egg parasitism, and egg survival exceeded 95% in each of 2 years. A new species of nematode (Steinernema sp.) (Nematoda: Steinernematidae) was recovered from pronymphs. Homaspis interruptus (Provancher) (Hymenoptera: Ichneumonidae) parasitized larvae and emerged from 8.5% and 2.8% of the pronymphs in two populations.


HortScience ◽  
2020 ◽  
Vol 55 (6) ◽  
pp. 851-857
Author(s):  
Lisa Tang ◽  
Sukhdeep Singh ◽  
Tripti Vashisth

In the past decade, FL citrus industry has been struck by Huanglongbing (HLB), a disease caused by the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas). Besides tree decline, HLB causes a sharp increase in mature fruit drop before harvest, leading to a substantial reduction in citrus production. The aim of the study was to provide insights in HLB-associated mature fruit drop. For HLB-affected ‘Valencia’ and ‘Hamlin’ sweet orange (Citrus sinensis), trees exhibiting severe symptoms (“severe trees”) had a significantly higher rate of mature fruit drop compared with mildly symptomatic ones (“mild trees”). Interestingly, dropped fruit were smaller than those still attached to tree branches regardless of the symptom levels of trees; overall, fruit of severe trees were smaller than mild trees. The result suggests a negative effect of HLB on fruit growth that may lead to a high incidence to drop subsequently at maturity. This possibility is further supported by the difference in immature fruit size as early as 2 months after bloom between severe and mild trees. Although HLB-triggered phloem plugging due to callose deposition in citrus leaves, which results in disrupted carbohydrate transport, has been documented in literature, the results of the histological analysis demonstrated no consistent pattern of callose deposition in the mature fruit pedicel in relation to the drop incidence. Additionally, sugar concentration in juice was not significantly different between dropped and attached fruit, providing evidence that carbohydrate shortage is not the case for dropped fruit and thus not the predominant cause of HLB-associated mature fruit drop. Notably, the midday water potential was significantly lower for severe than mild trees during the preharvest period (2 weeks before harvest of the current crop) in late March, which was also the second week after full bloom of return flowering. This suggests that altered tree water status due to HLB might limit fruit growth during the initial stage of fruit development (immediately after flowering) and/or increase the incidence of mature fruit abscission, leading to elevated preharvest fruit drop. Together, the results suggest that in the presence of HLB, strategies to increase fruit size and minimize additional stresses (especially drought) for the trees may improve mature fruit retention.


2021 ◽  
Vol 17 (29) ◽  
pp. 128
Author(s):  
Christelle Flavie Mbieji Kemayou ◽  
Grâce Annih Mbong ◽  
Marie Caroline Momo Solefack ◽  
Jean Kuate

La présente étude s’inscrit dans le cadre de la valorisation des mangues locales et de la perception endogène des pratiques culturales associées. Cette étude a été menée entre mars et juin 2020, dans les Départements du Noun et de la Lékié, dans onze (11) villages à fort potentiel de manguiers. L’enquête s’est faite par administration des questionnaires et par des observations directes auprès de 300 producteurs de mangues locales. Il en ressort que les producteurs sont en majorité des hommes (82,66%) mariés, de plus de 50 ans (59,3%), de niveau primaire (60%) pour le Noun et secondaire (59,3%) pour la Lékié. Les surfaces exploitées sont de moins de 1000 m2, localisées au bord de leurs concessions. Dans les deux Départements, l’itinéraire technique telle que recommandée par les experts n’est pas respecté et les techniques de récolte pratiquées sont inappropriées. Elles se font soit par la grimpe, la secousse de l’arbre ou l’utilisation des crochets. Les fruits récoltés sont mal conditionnés et vendus dans les différents contenants. L’anthracnose (Colletotrichum gloeosporiodes) et la chute de fruits immatures sévissent dans les vergers. Huit variétés locales ont été identifiées. Pour une bonne production des mangues locales dans le Noun et la Lékié il est important pour les producteurs d’améliorer leur capacité, d’utiliser les variétés locales greffées et de se former en techniques de conservation des mangues.  This study is part of the valorisation of local mangoes and the endogenous perception of associated cultivation practices. This study was carried out between March and June 2020, in the Noun and Lékié Divisions, in eleven (11) villages with high potential for mango trees. The survey was carried out by administering questionnaires and by direct observations with 300 local mango producers. It appears that the majority of producers are married men (82.66%), over 50 (59.3%), primary (60%) for the Noun and secondary (59.3%) for the Lékié. The areas exploited are less than 1000 m2, located at the edge of their concessions. In both Divisions, the technical itinerary as recommended by the experts is not followed and the harvesting techniques practiced are inappropriate. They are done either by climbing, shaking the tree or using the hooks. The harvested fruits are poorly packaged and sold in the various containers. Anthracnose (Colletotrichum gloeosporiodes) and immature fruit drop are rampant in orchards. Eight local varieties have been identified. For a good production of local mangoes in Noun and Lékié it is important for producers to improve their capacity, to use grafted local varieties and to be trained in mango conservation techniques.


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