Maciej A. Pszczolkowski

Prospects of Monosodium Glutamate Use for Enhancement of Spinosad Toxicity Against Codling Moth Neonates

It was demonstrated that neonates of the codling moth,Cydia pomonella (L.), feed on ‘Red Delicious’ apple leaves and successfully molt to the second instar. Next, using a non-choice bioassay, we targeted codling moth neonates feeding on apple leaves, with standard concentrations of a culinary taste enhancer, monosodium glutamate (MSG), and Success®, which contains 22.8% spinosad as its active ingredient. The addition of 25 ppm MSG increased feeding by 20–30%. Stimulatory properties of MSG were preserved in the presence of 12.5 ppm Success, and mortality from a 12.5 ppm Success + 25 ppm MSG combination increased by factors of 3.1–1.6 compared with Success alone. In a field experiment without rain, MSG maintained its stimulatory properties for 24 h, increasing feeding by 37%. Consistently, without rain, MSG increased the toxicity of Success in the field by a factor of × 3.5. However, the stimulatory properties of MSG dropped to 19% with 4.3 mm of rain, and to zero with 9.6 mm of rain. Increased Success toxicity by MSG was reduced to × 1.6 with 4.3 mm of rain, and dropped to zero after 9.6 mm of rain. It is concluded that MSG seems to be a promising feeding stimulant, enhancing the toxic properties of Success which itself is a good candidate for codling moth control. However, field persistence of MSG needs to be improved, either by formulating the Success + MSG combination into some field-stable matrix, or by employing a sparingly water-soluble substance mimicking MSG’s action as a feeding stimulant in codling moth neonates.

Circadian dynamics of locomotor activity and deltamethrin susceptibility in the pine weevil,Hylobius abietis

Rhythmic locomotor activity and daily susceptibility to deltamethrin were tested in the pine weevil,Hylobius abietis (L.) (Coleoptera, Curculionidae), a pest of young conifer plants. In constant darkness, beetles revealed a free-running circadian pattern of locomotor activity (average period 22h : 20min). Under long photoperiod, L:D 18:6, entrainment of motor activity was observed. In the entrained population of the weevils, a peak of locomotor activity occurred at about the beginning of the dark phase, and the minimum occurred in the middle of the light phase. Fluctuations of susceptibility to a standard dose of deltamethrin (0.5 μg/g body weight) varied across the day, and were inversely correlated to the changes in locomotor activity. The importance of considering the daily organization of insect biology in studying insect resistance to pesticides is re-emphasized.

Single experience learning of host fruit selection by lepidopteran larvae

Neonate larvae of a lepidopteran, the codling moth (Cydia pomonella L.) search for their host fruit after hatch. The process of host searching is known to be activated by kairomones contained in host fruit volatiles, but the mechanism of actual selection and infestation of the fruit is unclear. Here we show that lepidopteran neonates can utilize single experience learning in selection and infestation of host apple. We found that the process of host fruit selection may be modified by single experience learning, namely preference induction or averse conditioning. Both types of learning were acquired within 3 h of training. Experience was retained for over 3 days in the case of averse conditioning. Preference induction, a form of learning specific to insects, is expected to produce rigid host preference lasting for days if not weeks, but in codling moth neonates this type of memory was retained only for 3 h. We speculate that conjunction of preference induction with short retention time and averse conditioning with long retention time provide an optimal adaptive strategy of host fruit selection for codling moth neonates.

Feeding and Development of Cydia pomonella (Lepidoptera: Tortricidae) Larvae on Apple Leaves

Abstract We present leaf consumption, maximum body weight, head capsule width, and testicular ultrastructure of four sequential instars in codling moth reared solely on apple leaves of Honeycrisp variety. The developmental parameters for Cydia pomonella (L.) larvae fed on leaves are compared with those reared on artificial diet. Head capsules in the second, third, and fourth instars reared on leaves were significantly smaller than those in larvae fed artificial diet. Maximum body weights were significantly lower in all instars fed leaves compared with larvae fed artificial diet. More than 60% of larvae fed leaves molted to the third instar, and ≈3% entered the fifth instar, but none pupated, demonstrating an inability to fully compensate for the reduced nutritive value of a leaf-based diet. A study of testicular ultrastructure revealed that feeding codling moth larvae exclusively on apple leaves allowed formation of testes, but also triggered an intense, abnormal autophagocytosis that caused premature senescence of this tissue.

Effects of Ginkgo biloba Constituents on Fruit-Infesting Behavior of Codling Moth (Cydia pomonella) in Apples

Codling moth, Cydia pomonella (L.), is a cosmopolitan pest of apple, potentially causing severe damage to the fruit. Currently used methods of combating this insect do not warrant full success or are harmful to the environment. The use of plant-derived semiochemicals for manipulation with fruit-infesting behavior is one of the new avenues for controlling this pest. Here, we explore the potential of Ginkgo biloba and its synthetic metabolites for preventing apple feeding and infestation by neonate larvae of C. pomonella. Experiments with crude extracts indicated that deterrent constituents of ginkgo are present among alkylphenols, terpene trilactones, and flavonol glycosides. Further experiments with ginkgo synthetic metabolites of medical importance, ginkgolic acids, kaempferol, quercetin, isorhamnetin, ginkgolides, and bilobalide, indicated that three out of these chemicals have feeding deterrent properties. Ginkgolic acid 15:0 prevented fruit infestation at concentrations as low as 1 mg/mL, bilobalide had deterrent effects at 0.1 mg/mL and higher concentrations, and ginkgolide B at 10 mg/mL. On the other hand, kaempferol and quercetin promoted fruit infestation by codling moth neonates. Ginkgolic acids 13:0, 15:1, and 17:1, isorhamnetin, and ginkgolides A and C had no effects on fruit infestation-related behavior. Our research is the first report showing that ginkgo constituents influence fruit infestation behavior and have potential applications in fruit protection.

Effect of sugars and non-nutritive sugar substitutes on consumption of apple leaves by codling moth neonates

Recently we reported that monosodium glutamate stimulates feeding in neonates of the codling mothCydia pomonella (L.). Herein we extend our general knowledge about feeding stimulators in neonates of this species, by presenting the effects of several sugars (sucrose, glucose, fructose, and maltose) and non-nutritive sugar substitutes (Sweet’n Low® and Equal®) on consumption of apple leaf (HoneycrispTM) tissue. Glucose, fructose, maltose and aspartame-based Equal had no effect on leaf consumption. Sucrose at a high concentration significantly reduced leaf consumption and delayed commencement of feeding. Sweet’n Low at high concentrations significantly increased leaf consumption and accelerated the commencement of feeding. Saccharin hemicalcium salt was identified as an active ingredient of Sweet’n Low. At 500 ppm and 1000 ppm, saccharin hemicalcium salt increased leaf consumption and accelerated commencement of feeding. The practical aspects of our findings are discussed.

Effects of calcium and glutamate receptor agonists on leaf consumption by lepidopteran neonates

Calcium and glutamate receptor (GluR) agonists affect apple leaf consumption by neonates of the apple pest, the codling moth, Cydia pomonella (L.) Initial apple leaf consumption was advanced by the presence of trans-1-amino-(1S,3R)-cyclopentanedicarboxylic acid (trans-ACPD), but not by calcium chloride or N-methyl-D-aspartate (NMDA). However, during the 3 h following hatch, CaCl(2) and NMDA increased the quantity of apple leaf tissue consumed, but trans-ACPD had no such effects. Stimulatory effects of CaCl(2) and NMDA on leaf consumption were abolished if codling moth larvae were concurrently exposed to calcium chelator EDTA. (RS)-alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropanoic acid (AMPA) and kainic acid had no effects either on commencement or intensity of leaf consumption. We hypothesize that in codling moth larvae, apple leaf consumption is induced via metabotropic GluR, and sustained feeding is regulated via NMDA GluRs. Practical aspects of this finding are discussed.

Chilling affects allatal cell proliferation via antennae and protocerebral neurons in the cockroach Diploptera punctata.

The corpora allata (CA) cells in a mated female of the cockroach Diploptera punctata undergo numerous mitotic divisions before an increase in juvenile hormone synthesis. A previous study demonstrated that this mitotic wave could be suppressed by exposure of the mated female to melting ice. Herein, we report that chilling suppresses CA mitosis via antennal perception. Cell proliferation-suppressing stimuli from chilling were acquired in proportion to the length of time of exposure to the low temperature and the physical length of the antennae exposed to chilling. Sixty basal antennal annuli should remain exposed to chilling for at least 1.5 h in order to suppress mitotic divisions in CA. Mitotic divisions in corpus allatum are suppressed by stimuli from contralateral antenna, predominantly via pars intercerebralis neurons. Selective disconnection of pars intercerebralis neurons from CA, prior to chilling, restored the mitotic wave in CA. Cellular divisions did not occur in CA of chilled females if either pars lateralis neurons were severed or left intact.

Enhancement of spinosad toxicity toCydia pomonella neonates by monosodium glutamate receptor agonist

Recently, we reported that monosodium glutamate (MSG) is a feeding stimulant and an enhancer of pesticide toxicity against neonates of the codling moth. Herein, we show that a MSG alternative,trans-1-aminocyclobutane-1,3-dicarboxylic acid (trans-ACBD), alone or in the presence of spinosad (Success®), increases leaf tissue consumption by codling moth neonates. In contrast to MSG,trans-ACBD maintains its feeding stimulatory properties in the field even after 20 mm of simulated rain, and effectively increases spinosad efficacy in both laboratory and field experiments.

Predicting Emergence in a Midwestern Population of the Green June Beetle, Cotinis nitida (L.) (Coleoptera: Scarabaeidae)

ABSTRACT:  Green June beetle, Cotinis nitida (L.), is an important pest of grapes, peaches, blackberries, blueberries, apples, and pears, yet cumulative degree days that this species requires for outbreak have not been delineated. We monitored green June beetle populations in Mountain Grove, Missouri, USA, for five consecutive years (2009–2013) using traps baited with isopropanol. Our results show that cumulative degree day (CDD) calculation with starting point of March 1st, single sine method of calculation, and 10°C as the base temperature may be used for forecasting green June beetle population dynamics. Five year average ± SE was 888.96 ± 36.78 CDD for the first catch of the green June beetle and 1237.68 ± 25.31 CDD for peak trap catch. Our data also suggest that in the relatively rainy environment in Mountain Grove, the departures from the five year average observed in a given year were not correlated with precipitation preceding the first flight and peak activity of green June beetle populations.