Susceptibility of potato plants grown from tubers irradiated with stimulation doses of gamma irradiation to potato tuber moth, Phthorimaea operculella Zeller (Lep., Gelechiidae)

The feeding behaviour of potato tuber moth, Phthorimaea operculella Zeller (Lep., Gelechiidae), reared on leaves and tubers of potato plants, which were irradiated as seed (tubers) with stimulation doses of gamma irradiation (1, 3, 5 and 10 Gy), was studied. Significant differences in the larvae and pupae developmental time, pupal weight, mortality, fecundity and percentage egg hatch, were observed between insects fed on plants which resulted from the irradiated seeds and those of the control. It appears that leaves of potato plants grown from irradiated seeds particularly those of 3 Gy, became more attractive to the larvae, although the resulting tubers, with the exception of those of 10 Gy, became more resistant to potato tuber moth. Storing the tubers at ambient temperature conditions affected the degree of larval sensitivity. The leaves and tubers of 10 Gy-irradiated seeds became more suitable for insect development, indicating that the later dose may inhibit the production of secondary plant metabolities and chemical compounds.     

A potential threat to tomato,a congener crop to potato from invaded potato tuber moth,Phthorimaea operculella (Zeller)

Potato tuber moth (PTM) is a primary pest of potato which had invaded into Korea in 1968 and its distribution was restricted in the southern part of the peninsula. Possibly due to the climate change, its distribution expanded toward the Northern part of South Korea including Gyounggi and Gangwon province where tomato production is high. Host expansion and damage potential of PTM was evaluated on tomato, a congeneric crop of potato. Three commercial varieties of tomato (Dafnis, Bangul and Jujube) and a potato (Superior-Sumi) were subjected to PTM larvae. The results showed that host suitability of tomato to PTM was lower than potato, but PTM could completely develop and reproduce on tomato leaves or fruits. Development time was varied relative to tomato varieties and plant age. PTM showed lower performance on the leaves and fruits of cherry type tomatoes. Higher survival was observed in the large sized fruit of tomato varieties. This study showed substantial evidence that the invaded PTM could damage the tomato cultivation.     

Transgenic Tobacco and Apple Plants Expressing Biotin-binding Proteins are Resistant to two Cosmopolitan Insect Pests,Potato Tuber Moth and Lightbrown Apple Moth,Respectively

Tobacco (Nicotiana tabacum cv. Samsun) and apple (Malus x domestica cv. Royal Gala) plants expressing avidin or strepavidin were produced using Agrobacterium tumefaciens-mediated transformation. ELISA assays showed that avidin expression ranged from 3.1 to 4.6 microM in tobacco and from 1.9 to 11.2 microM in apple and streptavidin expression ranged from 11.4 to 24.5 microM in tobacco and from 0.4 to 14.6 microM in apple. Expressed at these levels, both biotin-binding proteins conferred a high level of insect resistance on transformed tobacco plants to larval potato tuber moth (PTM), Phthorimaea operculella (Zeller) (fam. Gelechiidae) and on apple plants to larvae of the lightbrown apple moth (LBAM) Epiphyas postvittana (Walker) (fam. Tortricidae). More than 90% of PTM larvae died on tobacco plants expressing either avidin or streptavidin genes within 9 days of inoculation. Mortality of LBAM larvae was significantly higher (P < 0.05) on three avidin-expressing (89.6, 84.9 and 80.1%) and two streptavidin-expressing (90 and 82.5%) apple plant lines than on non-transformed control plants (14.1%) after 21 days. Weight of LBAM larvae was also significantly reduced by feeding on all apple shoots expressing avidin and on apple shoots expressing streptavidin at levels of 3.8 microM and above.     

Biological Control of the Potato Tuber Moth (Phthorimaea operculella Zeller) in the Republic of Yemen Using Granulosis Virus: Biochemical Characterization, Pathogenicity and Stability of the Virus

A granulosis virus infecting the potato tuber moth, Phthorimaea operculella, has been identified, isolated and purified from diseased potato tuber moth larvae collected from potato fields in the highland basin Qa al-Boun of the Republic of Yemen. The granulosis virus was propagated by feeding potato tuber moth larvae with potatoes treated with a concentration of one granulosis virus-infected fourth instar larva to 5l of water (corresponding to an occlusion body (OB) concentration of 2 106 OB ml-1). Restriction enzyme analysis of viral DNA revealed that the isolated virus seemed to correspond to an isolate from the Lima region of Peru. A median LC 50 value of 7.3 104 OB ml-1 was calculated for a purified virus preparation. Different preparations of the granulosis virus were investigated for their persistence in the field on tubers and leaves. A purified virus preparation (PoGV) applied to potato tubers and exposed in the open had a half-life of 1.3 days. On leaves, the activity of granulosis virus spray deposits of an unpurified virus preparation (PoGV I) and of a glycerine-formulated preparation (PoGV II) also declined with exposure time. Mortalities of potato tuber moth larvae of 43% for PoGV I and 49% for PoGV II were recorded when first instar larvae were fed with potato leaves collected 2 days after treatment. After 8 days, 25.8% of the larvae had died from PoGV I treatment and 19.4% from PoGV II. Neither preparation displayed any effect 17 days after application.     

Evaluation of potato tuber moth (Lepidoptera: Gelechiidae) resistance in tubers of Bt-cry5 transgenic potato lines

The potato tuber moth, Phthorimaea operculella (Zeller), in tropical and subtropical countries, is the most destructive pest of potato, Solanum tuberosum L. The larvae attack foliage and tubers in the field and in storage. The purpose of this study was to evaluate the efficacy of a Bt-cry5 transgene to control the potato tuber moth in tuber tissues. Tuber bioassays using stored (11-12 mo old) and newly harvested tubers of Bt-cry5-Lemhi Russet and Bt-cry5-Atlantic potato lines showed up to 100% mortality of 1st instars. Mortality was lowest in the newly harvested tubers of Bt-cry5-Atlantic lines (47.1-67.6%). Potato tuber moth mortality was 100% in the Bt-cry5-Spunta lines that were transformed with Bt-cry5 gene controlled by the CaMV 35S promoter (pBIML5 vector) and in 2 of 3 lines transformed with Bt-cry5 gene controlled by the Gelvin super promoter (pBIML1 vector). The transgenic Spunta lines expressing Bt-cry5 controlled by the patatin promoter (pBMIL2 vector) showed the lowest tuber moth mortality (25.6 and 31.1%). The Bt-cry5 transgenic lines with high tuber expression of B. thuringiensis have value in an integrated pest management system to control potato tuber moth.     

Overcompensating plants: their expression of resistance traits and effects on herbivore preference and performance

Overcompensation is a plant tolerance response in which plants have higher fitness after herbivory than without damage. Although it has been demonstrated that plants are able to simultaneously express resistance and tolerance traits, it remains unclear whether overcompensating plants are also inducing resistance‐mediating secondary metabolite production and how herbivores perform on plants that overcompensate. Our previous work has shown that a potato variety [Solanum tuberosum L. cv. Pastusa Suprema (Solanaceae)] from Colombia can express overcompensatory responses to damage by larvae of the Guatemalan potato moth, Tecia solanivora Povolny (Lepidoptera: Gelechiidae). Here we investigated (1) whether potatoes that express overcompensatory responses also induce resistance traits and (2) how the previous damage affects Guatemalan potato moth preference and performance. Our results show that larval feeding not only systemically induces higher tuber biomass but also an increased production of resistance‐related compounds, such as phenolics and proteinase inhibitors. Pupal mass increased with increasing tuber size, whereas changes in tuber secondary metabolism did not correlate with any metric of larval performance. Oviposition preference did not change between induced and undamaged plants. Our data show that potato plants expressing overcompensatory responses also induce secondary compounds known to increase resistance against herbivores. However, the induced response was relatively small, reducing the opportunities for a negative effect on the herbivore. Hypotheses for why larvae perform better in larger tubers and are not affected by the secondary metabolism are discussed. From an ecological and agricultural point of view, our results suggest that the expression of overcompensatory traits could have positive effects on herbivore performance.     

Biological Control of the Potato Tuber Moth (Phthorimaea operculella Zeller) in the Republic of Yemen Using Granulosis Virus: Propagation and Effectiveness of the Virus in Field Trials

A granulosis virus (PoGV) infecting the potato tuber moth, Phthorimaea operculella, in the Republic of Yemen was evaluated for its use in an inundative approach to control this pest. In field trials on potatoes, the effectiveness of the virus was examined on-farm and on-station using an unpurified preparation (PoGV I) and a purified glycerine-formulated virus preparation (PoGV II). The virus infection and mortality of potato tuber moth larvae were dependent on the virus concentration applied. After application of 5 1012 occlusion bodies (OB) ha-1 of PoGV I, the proportion of virus-infected larvae increased, fluctuating between 26 and 39% 14-35 days after treatment. At a granulosis virus concentration of 5 1013 OB ha-1, clear symptoms of granulosis virus infection (milky white coloration and reduced vitality) were observed in larvae collected 11 days after treatment. A total of 70% of the fourth instar larvae collected 19 days after treatment with PoGV I were infected. Further observations revealed very high rates of effectiveness in terms of larval mortality. The preparations PoGV I and PoGV II were not found to differ in their degree of effectiveness, which resulted in a mortality of potato tuber moth larvae of 85.3% for PoGV I and 82.5% for PoGV II respectively.     

Population dynamics of the potato tuber moth on processing tomatoes in Israel

The potato tuber moth (PTM),Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is a major pest of processing tomatoes,Lycopersicon esculentum Mill. (Solanaceae), in Israel. The larvae penetrate the tomato fruit through the stem end and present a serious threat to crop quality. Foliage and fruit samples were taken in nine commercial tomato fields located in Israel's three main tomato growing areas, two of which are potato growing areas as well. PTM was not found where potatoes were absent. Potato harvest in nearby fields was found to be the most significant factor affecting seasonal trends in PTM population density in tomatoes. All four larval instars were found in foliage on all sampling dates. Significantly higher proportions of first instars were found during the population density increase which followed potato harvest. Damaged fruits did not contain first instar larvae, indicating that PTM never undergoes complete development within tomato fruit. Fruit damage levels at harvest were positively correlated to the peak mean population densities on foliage and the date they were observed. In tomato fields not adjacent to potatoes, infestation was first observed at the edge of the field. Both before and after the potato harvest in nearby fields, population density at the edge of the field was significantly higher than at the center. In tomato fields adjacent to potatoes, no significant differences were found between population densities at the edge and center before the potatoes were harvested. After the potato harvest, population density at the center of tomato fields was higher than at the edge. Deceased, October 1988     

Effects of gamma irradiation used to inhibit potato sprouting on potato tuber moth eggs Phthorimaea operculella Zeller (Lep., Gelechiidae)

Abstract: Different age groups of potato tuber moth, Phthorimaea operculella Zeller, eggs were exposed to gamma irradiation at incremental doses up to 150 Gy (the upper dose limit allowed for potato sprout inhibition). Young eggs were more likely to be sensitive to gamma irradiation than older eggs and the sensitivity level declined with age of the eggs. The exposure of 3–3.5-day-old eggs to 150 Gy resulted in a 26% increase in the egg incubation period compared with unirradiated eggs. The minimum dose required to prevent 4–4.5-day-old eggs from hatching was 1 kGy. When eggs were exposed to 75 Gy, 9.7% of larvae survived to the adult stage but emerged as deformed moths. At 100 and 125 Gy, 10.2 and 9.6% of larvae pupated, respectively, although no adult eclosion was recorded, whereas at 150 Gy, the larvae remained in mid-instar stage and eventually died. Gamma irradiation doses applied to inhibit potato sprouting could be also considered as a valuable control tool against potato tuber moth infestations.     

Spatial and temporal dynamics of potato tuberworm (Lepidoptera: Gelechiidae) infestation in field-stored potatoes

The potato tuberworm, Phthorimaea operculella (Zeller), is a major pest of potatoes in fields and traditional storage. A common method of nonrefrigerated storage is to pile potatoes in straw-covered heaps in the field. Tubers may be stored up to 3-4 mo in this manner, until the next harvest. We studied the dynamics of potato tuber moth infestation associated with such field storage in a 12-wk experiment in Israel. We set up six potato heaps, and sampled them for potato tuber moth at different locations at weekly intervals. Potato tuber moth infestation was significantly higher at the perimeter of the heaps than at their center, but it did not differ between bottom, mid-height, and top of the heaps. The proportion of potato tuber moth-infested potato tubers increased from 10 to 65% over the course of the experiment, and the mean number of potato tuber moth larvae per tuber increased from 0.25 to 2.50. Potato tuberworm populations increased sharply after 3, 6, and 9 wk of study, possibly corresponding to successive generations that developed within the heaps. This interpretation is supported by calculations of potato tuberworm generation length based on temperature data. Catches in pheromone traps that were placed near the heaps were not correlated (spatially and temporally) with potato tuberworm densities within heaps, hinting that migration among heaps did not considerably affect within-heap population dynamics. Potato tuberworm levels were not correlated with ambient temperatures, perhaps because of the warm, humid, and constant microclimate within the heaps. We discuss the significance of our findings for control efforts of the potato tuberworm.     

Potential for high hydrostatic pressure processing to control quarantine insects in fruit

Tests were conducted to determine the potential for high hydrostatic pressure (HPP) to control codling moth, Cydia pomonella (L.), and western cherry fruit fly, Rhagoletis indifferens Curran. Apples (Malus spp.) with codling moth larvae or eggs were treated at 24 and 72 h, respectively, after infestation at a series of pressures between 14,000 and 26,000 pounds per inch2 (psi). Survivorship was determined the next day for larvae and after 10 d for eggs. Codling moth eggs were more tolerant of HPP treatment than larvae. Mortality of larvae was 97% at 22,000 psi, whereas mortality of eggs at this dose was 29% and not significantly different from the untreated controls. In a second study, no codling moth eggs hatched at any high pressure treatment between 30,000 and 80,000 psi, indicating these pressures were lethal. Various stages of western cherry fruit fly were treated at pressures from 10,000 to 45,000 psi, and survivorship was determined after 24 h. Eggs and third instars were more tolerant of HPP than the first and second instars. Mortality was 100% in western cherry fruit fly eggs and larvae at pressures > or =25,000 psi. Apple and sweet cherry quality after high pressure treatment was poor, but high pressure may have applications to control quarantine pests in other fruits.     

Pupation site preference and body orientation of the potato tuber moth, Phthorimaea operculella

ABSTRACT. Pupation site preference and body orientation of potato tuber moth larvae, Phthorimaea operculella Zeller (Geleehiidae), were examined in the laboratory. The larvae preferred a dry, enclosed, dark place as their pupation site. Dryness was the strongest of the three categories of stimulus; the second was stimuli evoking thigmotaxis; the third was darkness. Having selected a pupation site, a larva oriented its head to the open side of the site. If two or more openings were present, final orientation was influenced by light and gravity. These preferences and orientation habits enhance pupal protection, and the ultimate successful exit of the adult pupation crevices.     

Laboratory evaluation of lufenuron on immature stages of potato tuber moth (Lepidoptera: Gelechiidae)

The effects of the chitin synthesis inhibitor lufenuron against potato tuber moth, Phthorimaea operculella (Zeller), eggs were determined by topically exposing different age groups of eggs (1-4 d old) to treated potato tubers (Solanum tuberosum L.) under laboratory conditions. Larval hatch from both treated (4 and 12 g [AI]/100 liter) and untreated tubers was >95%, but mortality of first instars was high in treated tubers (>90%) compared with untreated tubers. Examination of the treated tubers showed that most of the larvae were unable to penetrate or cause any noticeable damage to the potato tubers. However, the few first instars that survived were able to penetrate the tubers and continue their development to the pupal or adult stages. At 12 g (AI)/100 liter, adult emergence was <2% and most of the emerged adults had morphological deformities such as reduced wing size and they were unable to free themselves from the pupal sacs. These data suggest that topical application of lufenuron to eggs before larval hatch would reduce the amount of damage caused by potato tuber moth as part of integrated pest management program.     

用马铃薯人工饲养马铃薯块茎蛾的方法

介绍一种马铃薯块茎蛾Phthorimaeaoperculella的室内人工饲养方法。在人工养虫室内用 1 0 %的蜂蜜水喂养成虫 ,用滤纸收集卵块 ,幼虫在薯块上饲养 ,化蛹于牛皮纸卷成的纸筒中 ,饲养结果发现马铃薯块茎蛾完成 1代大约需要 35～ 4 6d ,室内连续饲养块茎蛾 3代 ,卵的孵化率、幼虫化蛹率、成虫羽化率均在 90 %以上。     

Polyribosomes from aging apple and cherry fruit

The sequence of events which occurs during the ripening of the Passe-Crassane pear fruit have been previously studied. In this work, we have investigated the ripening of another climacteric fruit (Pyrus malus L. cv Golden Delicious) and of a nonclimacteric fruit (Prunus avium L. cv Bigarreau Napoléon). We show that both climacteric fruits exhibit the same preclimacteric sequence of events. Differences exist, however, between the Golden Delicious apple and the Passe-Crassane pear in that the protein synthesis capacity of the two fruits is not the same during the over-ripening period. On the other hand, a nonclimacteric fruit, the Bigarreau Napoléon cherry, does not show an increase in its protein synthesis capacity during the over-ripening period.     

Establishment of Beauveria bassiana as a fungal endophyte in potato plants and its virulence against potato tuber moth,Phthorimaea operculella (Lepidoptera: Gelechiidae)

The potato tuber moth, Phthorimaea operculella, is the most damaging potato pest in the world and is difficult to control as the larvae are internal feeders in the foliage and tubers. Entomopathogenic fungi that colonize plants as endophytes have lethal and sublethal pathological effects on insect pests. We show that Beauveria bassiana colonizes the aerial parts of potato plants endophytically after inoculation through soil drenching. Endophytic B. bassiana persisted in potato foliage for more than 50 days postinoculation. Bioassays indicated that foliage of B. bassiana-inoculated potato plants were pathogenic against larvae of P. operculella. Sublethal experiments indicated that B. bassiana negatively affected the growth, development, and reproduction of P. operculella. Development experiments showed that the weight of P. operculella pupae reared on B. bassiana-colonized potato plants (4.25 mg) was significantly less than that of those reared on uninoculated control plants (8.89 mg). Compared with newly eclosed larvae fed on control plants, those fed on B. bassiana-inoculated plants had significantly lower survivorship, with only 17.8% developing to the adult stage. Oviposition of P. operculella females reared on B. bassiana endophytically colonized plants was significantly lower (35 eggs/female) than of those reared on uninoculated plants (115 eggs/female). This study demonstrates that endophytic B. bassiana can be a potential biological control agent for the control and management of P. operculella. Comparing pupal weights of P. operculella reared on potato plants inoculated with the B. bassiana strain GZGY-1-3 and on untreated control plants, pupae from the control plants were significantly heavier than those from treated plants.     

Down-regulation of a ripening-related beta-galactosidase gene (TBG1) in transgenic tomato fruits.

Exo-galactanase/beta-galactosidase (EC 3.2.1.23) activity is thought to be responsible for the loss of galactosyl residues from the cell walls of ripening tomatoes. Transgenic tomato plants (Lycopersicon esculentum Mill cv. Ailsa Craig) with reduced exo-galactanase/beta-galactosidase mRNA were generated to test this hypothesis and to investigate the role of the enzyme in fruit softening. A previously identified tomato beta-galactosidase cDNA clone, TBG1, was used in the experiments. Heterologous expression of the clone in yeast demonstrated that TBG1 could release galactosyl residues from tomato cell wall galactans. Transgenic plants showed a reduction in TBG1 mRNA to 10% of normal levels in the ripening fruits. However, despite the reduction in message, total beta-galactosidase and exo-galactanase activities were unaffected. Furthermore, there was no apparent effect on levels of cell wall galactosyl residues when compared with the control. It was concluded that during the ripening of tomato fruits a family of beta-galactosidases capable of degrading cell wall galactans are active and down-regulation of TBG1 message to 10% was insufficient to alter the degree of galactan degradation.     

Developmental regulation of phospholipase D in tomato fruits

The catabolism of phospholipids initiated by phospholipase D (PLD, EC 3.1.4.4) is an inherent feature of developmental processes that include fruit growth and ripening. In cherry tomatoes (Lycopersicon esculentum Mill.), soluble and membrane-associated PLD activities increased during fruit development, which peaked at the mature green and orange stages. The increase in PLD activity was associated with a similar increase in the intensity of a 92 kDa band as demonstrated by western blot analysis. A full-length cDNA having 2430 bp and encoding a putative polypeptide with 809 amino acids, was isolated using tomato RNA, RT-PCR and 5' and 3' rapid amplification of cloned ends (RACE). Analysis of the primary and secondary structures showed the presence of the C2 domain, the PLD domain and several other features characteristic of PLD alpha. Microtom tomato plants transformed with antisense PLD alpha cDNA, were similar to untransformed plants and showed normal fruit set and development. The ethylene climacteric was delayed by over 7 d in the antisense PLD fruits, indicative of a slower ripening process. The leaves and unripened fruits of antisense PLD microtom plants possessed lowered PLD activity and PLD protein, as demonstrated by western blotting. However, during ripening, PLD activity in the transgenic fruits was maintained at a higher level than that in the untransformed control. Immunolocalization of PLD in microtom tomato fruits revealed the cytosol-membrane translocation of PLD during fruit development. The ripe fruits of antisense PLD celebrity plants possessed lowered PLD expression and activity and showed increased firmness and red colour. These results suggest that the expression of antisense PLD cDNA could be variable in different tomato varieties. The potential role of PLD in ethylene signal transduction events is discussed.