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Appunti sulla situazione apistica in Sardegna: 1. il censimento
No full textThe results are reported of two studies effected at an interval of 5 years. A comparison of beekeeper characteristics,
apiary organization, rearing techinques and hygenic conditions showed the development of a more
rational apiculture
Osservazioni sulla densità di popolazione diLymantria disparl. nelle principali aree subericole della Sardegna
No full textA two year survey (1980·81) was carried out in zones adjacent to roads running through the principal
Sardinian cork growing regions. Every 5 km in each region, egg clusters were counted on 40
trees, i.e. 4 radial lines of 10 trees (each line directed towards one of the cardinal points). The
results showed a wide population density variability spectrum, indicating those areas likely to
suffer total defoliation; summer observations confirmed correspondence between egg cluster counts
and damage. Whereas populations in the north of the island showed the highest levels, in the south
they were at latency levels. This staggered population fluctuation may possibily be explanied by
different sub-populations having been formed due to the distance and natural barriers between the
two regions. The survey not only showed the importance of the insect's active and passive diffusion
phenomena in determining defoliation extension, but also verified that food availability is a major
factor in controlling population density. The relative scarcity in high density populations limited fecundity
and prolificity and at times starvation caused mass mortality in the larvae
La Degradazione dei manufatti lignei causata da insetti
Full text linkThe chief coleopters and isopters which attack wooden articles are reported, with particular reference
to pest identification for adequate control measures. Bio-ethologycal information useful for
pest diagnosis are supplied, as well as predisposing factors and control techniques
Dix ans d'observation sur l'entomofaune nuisible au Chêne-liège en Sardaigne, pour la protection de la forêt
Full text linkLepidopter infestation of Northern Sardinian cork-oaks was studied from 1964 to 1975. Data were obtained on population composition, factors influencing natural mortality, fluctuation rythms of the more important species, and on plant reaction to defoliation.67 species were observed, of which the most frequently noted phytophagous lepidopters were: (1)Dryobotodes eremitaFabr. and D.MonochromaEsp., - with latent fluctuation; (2)Tortrix viridanaL.,Ortollosia crudaSchiff. andSpudaea ruticillaEsp., - with temporary fluctuation; and (3)Phalera bucephalaL.,Malacosola neustriaL. andPorthetria dispar(L.), - with periodic fluctuation. P.dispar(L.) and M.NeustriaL. fluctuations occurred in cycles of approximately 9 years. Severe defoliation was observed in 1973 and 1974,Malacosomareaching maximum population density a
year earlier than Porthetria.Numerous natural mortality factors affected the population fluctuation ofPorthetria. Particularly significant was the impact of predators and parasites on the pre-imaginal stages as well as that of pathogenetic agents (e.g.
viruses, protozoa), although the effect of the latter varied from year to year and was not entirely related to larval population density. Apart from a 7- 10% sterility, eggs showed a mortality rate varying from 2.7% to 17.7% due
to the parasitesOoencyrtus kuwanai(How.) (Hym., Encyrtidae) andAnastatus disparisRuschka (Hym. Eupelmidae) and the predatorsDermestes lardariusL. (Col. Dermestidae) andHaplocnemus jejunusKiensenw. (Col. Melyridae).The numbers of parasites on the larvae were in direct proportion to the larval population density and varied from 4.8% to 80.5 %; the most frequently encountered wereSturmia scutellataR.D.,Exorista segregataRond.,Exorista larvarumL. (Dipt. Tachinidae) andSarcophagidae of AgriaandSarcophaga genera. The predatorCalasoma sychophantaL. (Col. Carabidae)
appeared in large numbers the year following a maximum population density of the host larva. In addition to the forementioned dipters, the following were also observed to emerge from thePorthetriachrysalides:Pales pavidaMeig. (Dipt. Tachinidae),Muscina stabulansFall. (Dipt. Muscidae),Pimpla instigatorF.,Theronia atalantaePoda (Hym., Ichneumonidae) andBrachymeria intermedia(Nees) (Hym., Chalcididae).Porthetriapopulation
fluctuations were also affected by ambiental factors and by a reduction in fecundity when population densities were at their highest.Malacosoma neustriaL., apart from being subject to the same parasites and pathogenetic agents asPorthetria, was particularly influenced byPales
pavidaMeig. andScambus malacosomaeSeyrig (a hymenopter parasite specific toMalacosomalarvae in cocoon).Gradations in the two defoliator populations are, therefore, regulated by a whole number of contemporary factors in which tachinids, ichneumonids and disease play the predominant role.Provided that spring rainfall exceeds 180 mm, completely defoliated cork-oaks recover their foliage within 15 to 20 days. The damage caused by parasitic attack is, thus, limited to a certain extent.As a result of the observations made on the dynamics and regulating factors of the main forest defoliator populations, it is proposed that specific chemical control be confined (1) to the years of progradation, (2) to the
period when the young larvae are present and (3) only to certain limited surfaces considered strictly necessary
I Defogliatori delle foreste aQuercus suberL.
No full textData are given on the biology, mortality factors and population dynamics ofLymantria disparL.,Malacosoma
neustriaL.,Tortrix viridanaL. andEuproctis chrysorrhoeaL. the most harmful lepidopters toQuercus
suberL. A revision of chemical, microbiological, biological, biotechnical and genetic control methods
applied in the relevant diffusion areas is also reported
Prospettive di lotta integrata nell'agrumicoltura sarda
Full text linkPreliminary integrated control trials were performed in two fruit growing
areas of Sardinia (Simaxis, Siniscola) in 1979.
On the orange groves of SimaxisPlanococcus citri(Risso) is the
most important phytophage, followed byPanonychus citriMc Gr. andDialeurodes citri(Ashm.).
The indigenous natural enemies ofPlanococcus {Anagyrus pseudococciGrlt.,Leptomastidea abnormisGrlt.,Chrysopasp.,Chilocorus bipustulatus(L.)) andPanonychus(Stethorus punctillumWeiss,Amblyseius stipulatusA.H.) do not occur in sufficient number to limit infestation and it is therefore
necessary to use chemical control with 2 treatments of white oil + methidathion
and an acaricide (chlorfenson + propargil).
This treatment has also contained infestation ofDialeurocleswhich is
also actively preyed byClitostethus arcuatus(Rossi).Cryptolaemus montrouzieriMuls.,Leptomastix dactylopii(How.) andProspaltella lahorensis(How.) were introduced to improve the biological
control ofPlalnococcusandDialeurodes.Ceratitis capitatais the most important phytophage or the clementine
crop in Siniscola. Populations are monitoring with withe traps baited with trimedlure
and reached a maximum of 150 males/trap/weck at the end or
October. Three treatments with hait-spray (protein hydrolysate + Fenthion)
proved insufficient to contain the infestation due to rain in September and
October. In November, although 40% or fruits were punctured, only 2%
contained live larvae.
Heavy aphid infestations (particularlyAplzis citricolaV.d.G.) were
recorded in June on around 50% of the shoots. One treatment with sclective
aphicides stopped the infestation without influencing beneficial predators
(mainly Coccinellids).
For the orange cultures in Siniscola, bait-spray applications limited
damage byCeratitisand no action was necessary against aphids, since infestations
were small and the plants had low susceptibility.
On the basis or these observations, for the different phytophages are
proposed some sample methodologics and the relative intervention thresholds
Impiego delBacillus thuringiensisBerl. nella lotta allaLymantria disparL. in boschi diQuercus suberL. 3: risultati della sperimentazione condotta nel 1992.
Full text linkThe study was carried out in a North Sardinian cork oak forest in 1992. To control the gypsy moth
population three commercial preparations ofB. thuringiensissubsp.kurstakiwere applied by helicopter:
Activator THK and Bactospeine at low volume and Foray 48B at ultra low volume, when
80-90% of the gypsy moth larvae were in 1st and 2nd instars. At 14d after treatment, Activator
(applied at 5 l/ha) did not cause significant population reductions, while Bactospeine (applied at 32
B.I.U./ha) and Foray 48B (applied at 31.75 B.I.U./ha) caused average mortalities respectively of
40 and 53%. All preparations showed a good compatibility with the activity of the gypsy moth
natural enemies. Smaller mortalities, compared with previous tests, seem to be related with the low
average temperatures, between 13.9 and 16.8°C, of the post-treatment week which slowed down
both feeding and metabolism of the larvae just when there was the largest amount of spores on the
foliage
Impiego del Bacillus thuringiensis Berl. nella lotta alla Lymantria dispar L. in boschi di Quercus suber L. II. Risultati della sperimentazione condotta nel 1991
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