Tuta absoluta (Meyrick) (Lep.: Gelechiidae) in Sardinia infests tomato and other cultivated and s... more Tuta absoluta (Meyrick) (Lep.: Gelechiidae) in Sardinia infests tomato and other cultivated and spontaneous solanaceous plants. In the laboratory, larvae developed on tomato leafs forming only one mine. A relationship among the head capsule width, the larval length and the mine length on leaves was found for each of the four larval instars. The population dynamics was studied from October to June in a non-heated tomato greenhouse, where four generations of the insect pest were recorded. Female oviposited preferentially in the upper part of the plant. Infestation level was low during winter and increased from April on, reaching a density of 4 larvae/compound leaf. The ectophagous parasitoid Necremnus near artynes parasitized 3,6% of larvae during the whole crop cycle. In field conditions, T. absoluta adults were found during the whole year, achieving a maximum density in summer. On potato plants, during the two winter and summer cycles, low infestation levels were recorded (<0.15 ...
Tuta absoluta (Meyrick) (Lep.: Gelechiidae ) in Sardinia infests tomato and other cultivated and ... more Tuta absoluta (Meyrick) (Lep.: Gelechiidae ) in Sardinia infests tomato and other cultivated and spontaneous solanaceous plants. In the laboratory, larvae developed on tomato leafs forming only one mine. A relationship among the head capsule width, the larval length and the mine length on leaves was found for each of the four larval instars. The population dynamics was studied from October to June in a non-heated tomato greenhouse, where four generations of the insect pest were recorded. Female oviposited preferentially in the upper part of the plant. Infestation level was low during winter and increased from April on, reaching a density of 4 larvae/compound leaf. The ectophagous parasitoid Necremnus near artynes parasitized 3,6% of larvae during the whole crop cycle. In field conditions, T. absoluta adults were found during the whole year, achieving a maximum density in summer. On potato plants, during the two winter and summer cycles, low infestation levels were recorded ( Neochry...
The tomato borer Tuta absoluta (Meyrick) is an invasive pest native to South America and since it... more The tomato borer Tuta absoluta (Meyrick) is an invasive pest native to South America and since its arrival in Europe the tomato production has faced severe yield loss. The complex of indigenous parasitoids that colonized this new host species was monitored in Southern Italy during 2009-2011, in some of the regions where T. absoluta was initially detected (Campania, Sardinia and Sicily) with the aim of identifying the parasitoid complex of the tomato borer as well as finding potential biocontrol agents of this invasive pest. The survey was carried out by sampling the tomato borer on open field and protected greenhouse crops, on wild secondary hosts and by exposing sentinel infested tomato plants. A quick shift of native parasitoids to the new invasive host was observed and the parasitoid complex associated to T. absoluta seems to follow the typical pattern of colonization on exotic pests. The recovered species were, in fact, mainly generalist idiobiont parasitoids causing low levels ...
The population structure and dynamics of the tomato leafminer Tuta absoluta were investigated in ... more The population structure and dynamics of the tomato leafminer Tuta absoluta were investigated in a protected tomato crop and on potato and tomato crops and Solanum nigrum plants under open-field Mediterranean climatic conditions (Sardinia) by captures in pheromone-baited traps and visual inspection of host plants. In the greenhouse crop, male captures and leaf infestation were low in winter and increased steadily in spring up to 797.3 males/trap/week and 6.4 mines/ leaf, respectively. Under open-field conditions, males were captured all year round with a peak in early September, concurrently with highest mean daily temperatures. Pest density in potato crops was very low (&lt;0.3 mines/leaf), as well as on S. nigrum (0.16 mines/ leaf). Conversely, high pest infestation was observed in tomato leaves (3.8 mines/leaf) and fruits (27% damaged fruits). Eggs, larvae and adults were detected over two consecutive winters, indicating that T. absoluta can develop continuously over the year under natural conditions. Parasitoids were recorded throughout the survey at low rates (≤16.1%). The most active beneficials were Necremnus tutae and Neochrysocharis formosa in protected and open-field crops, respectively. The tomato leafminer completed 6 generations in the greenhouse tomato crop during the winter-spring growing season, whereas in open-field crops the pest completed two generations on winter potato and 4-5 in spring-summer tomato. The degree-day model based on minimum and maximum temperatures reliably described the population dynamics in the protected crop, and estimated the completion of 7.4 generations per year under open-field Mediterranean conditions.
Geologically Sardinia is a raft which, for just under thirty million years, has been crossing the... more Geologically Sardinia is a raft which, for just under thirty million years, has been crossing the western Mediterranean, swaying like a pendulum from the Iberian to the Italian Peninsula. An island so large and distant from the other lands, except for its "sister" Corsica, has inevitably developed an autochthonous flora and fauna over such a long period of time. Organisms from other Mediterranean regions have added to this original contingent. These new arrivals were not randomly distributed over time but grouped into at least three great waves. The oldest two correspond with the Messinian salinity crisis about 7 million years ago and with the ice age, when, in both periods, Sardinia was linked to or near other lands due to a fall in sea level. The third, still in progress, is linked to human activity. Man has travelled since ancient times and for many centuries introduced allochthonous species to Sardinia which radically modified the native flora and fauna, but always at ...
Tuta absoluta (Meyrick) (Lep.: Gelechiidae) in Sardinia infests tomato and other cultivated and s... more Tuta absoluta (Meyrick) (Lep.: Gelechiidae) in Sardinia infests tomato and other cultivated and spontaneous solanaceous plants. In the laboratory, larvae developed on tomato leafs forming only one mine. A relationship among the head capsule width, the larval length and the mine length on leaves was found for each of the four larval instars. The population dynamics was studied from October to June in a non-heated tomato greenhouse, where four generations of the insect pest were recorded. Female oviposited preferentially in the upper part of the plant. Infestation level was low during winter and increased from April on, reaching a density of 4 larvae/compound leaf. The ectophagous parasitoid Necremnus near artynes parasitized 3,6% of larvae during the whole crop cycle. In field conditions, T. absoluta adults were found during the whole year, achieving a maximum density in summer. On potato plants, during the two winter and summer cycles, low infestation levels were recorded (<0.15 ...
Tuta absoluta (Meyrick) (Lep.: Gelechiidae ) in Sardinia infests tomato and other cultivated and ... more Tuta absoluta (Meyrick) (Lep.: Gelechiidae ) in Sardinia infests tomato and other cultivated and spontaneous solanaceous plants. In the laboratory, larvae developed on tomato leafs forming only one mine. A relationship among the head capsule width, the larval length and the mine length on leaves was found for each of the four larval instars. The population dynamics was studied from October to June in a non-heated tomato greenhouse, where four generations of the insect pest were recorded. Female oviposited preferentially in the upper part of the plant. Infestation level was low during winter and increased from April on, reaching a density of 4 larvae/compound leaf. The ectophagous parasitoid Necremnus near artynes parasitized 3,6% of larvae during the whole crop cycle. In field conditions, T. absoluta adults were found during the whole year, achieving a maximum density in summer. On potato plants, during the two winter and summer cycles, low infestation levels were recorded ( Neochry...
The tomato borer Tuta absoluta (Meyrick) is an invasive pest native to South America and since it... more The tomato borer Tuta absoluta (Meyrick) is an invasive pest native to South America and since its arrival in Europe the tomato production has faced severe yield loss. The complex of indigenous parasitoids that colonized this new host species was monitored in Southern Italy during 2009-2011, in some of the regions where T. absoluta was initially detected (Campania, Sardinia and Sicily) with the aim of identifying the parasitoid complex of the tomato borer as well as finding potential biocontrol agents of this invasive pest. The survey was carried out by sampling the tomato borer on open field and protected greenhouse crops, on wild secondary hosts and by exposing sentinel infested tomato plants. A quick shift of native parasitoids to the new invasive host was observed and the parasitoid complex associated to T. absoluta seems to follow the typical pattern of colonization on exotic pests. The recovered species were, in fact, mainly generalist idiobiont parasitoids causing low levels ...
The population structure and dynamics of the tomato leafminer Tuta absoluta were investigated in ... more The population structure and dynamics of the tomato leafminer Tuta absoluta were investigated in a protected tomato crop and on potato and tomato crops and Solanum nigrum plants under open-field Mediterranean climatic conditions (Sardinia) by captures in pheromone-baited traps and visual inspection of host plants. In the greenhouse crop, male captures and leaf infestation were low in winter and increased steadily in spring up to 797.3 males/trap/week and 6.4 mines/ leaf, respectively. Under open-field conditions, males were captured all year round with a peak in early September, concurrently with highest mean daily temperatures. Pest density in potato crops was very low (&lt;0.3 mines/leaf), as well as on S. nigrum (0.16 mines/ leaf). Conversely, high pest infestation was observed in tomato leaves (3.8 mines/leaf) and fruits (27% damaged fruits). Eggs, larvae and adults were detected over two consecutive winters, indicating that T. absoluta can develop continuously over the year under natural conditions. Parasitoids were recorded throughout the survey at low rates (≤16.1%). The most active beneficials were Necremnus tutae and Neochrysocharis formosa in protected and open-field crops, respectively. The tomato leafminer completed 6 generations in the greenhouse tomato crop during the winter-spring growing season, whereas in open-field crops the pest completed two generations on winter potato and 4-5 in spring-summer tomato. The degree-day model based on minimum and maximum temperatures reliably described the population dynamics in the protected crop, and estimated the completion of 7.4 generations per year under open-field Mediterranean conditions.
Geologically Sardinia is a raft which, for just under thirty million years, has been crossing the... more Geologically Sardinia is a raft which, for just under thirty million years, has been crossing the western Mediterranean, swaying like a pendulum from the Iberian to the Italian Peninsula. An island so large and distant from the other lands, except for its "sister" Corsica, has inevitably developed an autochthonous flora and fauna over such a long period of time. Organisms from other Mediterranean regions have added to this original contingent. These new arrivals were not randomly distributed over time but grouped into at least three great waves. The oldest two correspond with the Messinian salinity crisis about 7 million years ago and with the ice age, when, in both periods, Sardinia was linked to or near other lands due to a fall in sea level. The third, still in progress, is linked to human activity. Man has travelled since ancient times and for many centuries introduced allochthonous species to Sardinia which radically modified the native flora and fauna, but always at ...
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