İslam Saruhan

The Estimation of Adult and Nymph Stages of Aphis fabae (Hemiptera: Aphididae) Using Artificial Neural Network

ABSTRACT In this research, the estimation of adult and nymph stages and adult of Aphis fabae was investigated using artificial neural network. Determining A. fabae nymph stages is difficult. Morphometric study of different parts of an insects body is needed to obtain an index to distinguish between different immature stages. The study was aimed to develop a model of A. fabae nymph stages and adult using length of hind tibia, antenna and body length. It was found that the constructed artificial neural network (ANN) exhibited high performance for predicting A. fabae nymph stages. Correlation was 99% and the estimation of the best ANN model was determined to be 0.016289 at epoch 18. Software computing techniques are very useful tools for precision agriculture and also determining which method gives the most accurate result.

Discrimination of the Palomena prasina L. (Heteroptera: Pentatomidae) nymph stages and sex using some morphological parameters by the multiple regression analysis

Discrimination of different nymphal stages and sex (male and female) of insects is important in the morphological, physiological and toxicological studies under laboratory and field conditions. The morphometric study of different parts of an insect’s body is needed to obtain an index to distinguish between different nymphal stages and sex. In the hazelnut production area of the Black Sea region, amongst the sucking type bugs the green shield bug ( Palomena prasina L.) is the most important specie encountered due to its intensity and economical damage threshold. The study was aimed to develop modeling of the P. prasina nymph stages and sex (NSS) using body length and prothorax width. Eight regression equations were compared for accuracy and adaptability. The best model developed was as follows: NSS = 0.344 + 0.235W + 0.309L (R² = 0.9882), where NSS is nymph stages and sex, W is the prothorax width (cm) and L is the body length (cm). For validation of the model, estimated values for NSS showed strong agreement with the measured values. Therefore, it can be concluded that models presented herein may be useful for the estimation of the individual NSS with a high degree of accuracy. Key words: Modeling, body length, prothorax width, Palomena prasina , nymph stages.

SEX DISCRIMINATION OF ADULT CURCULIO NUCUM L. (COLEOPTERA: CURCULIONIDAE), A PEST OF HAZELNUTS IN TURKEY

The hazelnut weevil, Curculio nucum L., is the key pest of hazelnut (Corylus avellana L., Betulaceae) in many countries. Recently, increasing attention on the pest status of C. nucum in commercial orchards has accelerated the number of studies on its biology, behavior, and ecology (Ural, 1957; Tabamaishvili, 1988; Paparatti, 1990; Pucci, 1992; AliNiazee, 1997; 1998; Milenkovic and Mitrovic, 2001; Tuncer and Ecevit, 1997; Tuncer et al., 2001; Akça and Tuncer, 2005). At times, biological, behavioral, and ecological studies require researchers to determine the sex of adults without dissecting the genitalia and killing the organisms. Many earlier studies used the length of the rostrum in C. nucum as a criterion to distinguish their sex (Ural, 1957; Tabamaishvili, 1988; Sezen et al., 1999; Akça and Tuncer, 2005). In addition to this character, our previous study described several differences in average body size and elytral size between males and females in C. nucum. However, owing to large variation, sex discrimination using these characters, except rostral length, is not reliable. Rostral length is a good character to sex adult C. nucum [averaging 5.56 (4.926.65) and 3.96 (3.35-4.56) mm for female and male, respectively, differing significantly between sexes, t 0.05 (2), 49 = 30.2]; Akça and Tuncer, 2005). However, using rostral length is not convenient because it requires a device for measurement, and it appears to be affected by environmental factors. Also, the differences in rostral length can be as little as 0.5 mm, making it time-consuming and cumbersome to use, particularly for field applications (Akça and Tuncer, 2005). Duan et al. (1999) suggested the use of a suture dividing the last two abdominal tergites of males, instead of snout length, for sexing adult Anthonomus pomorum (Coleoptera: Curculionidae). Lykewise, Sappington and Spurgeon (2000) demonstrated that the tergal-notch in the eighth tergite of male Anthonomus grandis (Coleoptera: Curculionidae) is more accurate than snout characteristics for sexing the adults. This study describes a new, nondestructive character associated with abdominal tergites to discriminate male and female C. nucum adults. Volume 118, Number 1, January and February 2007 87

Evaluation of some entomopathogenic fungi against the fall webworm (Hyphantria cunea Durry, Lepidoptera: Arctidae)

Fall webworm ( Hyphantria cunea Durry, Lepidoptera: Arctidae) is an important pest infecting about 600 hosts. It is harmful especially in hazelnut orchards in the Black Sea Region and is becoming epidemic occasionally. It may cause damage in mulberry, cherry, apple, poplar, and willow beside hazelnut in the region. Due to having a polyphagous feeding behavior and a high reproduction power; fall webworm can spread rapidly and make difficult to manage. In the region, currently, mostly chemical control is applied against this pest. Due to adverse effects of the chemical control to the environment and to living organisms, it is inevitable to develop other alternative control methods for this pest. In this study, the effects of some entomopathogenic fungi isolates obtained from Palomena prasina which is another pest in hazelnut production areas, on H. cunea in laboratory conditions. Overall, 1x10 8 conidia mL -1 of concentration obtained from 2 isolates of Simplicillium lamellicola (TR-01 and TR-02) and 4 isolates of Lecanicillium muscarium (TR-04, TR-05, TR-07 and TR-08) was used against 3 rd period larva of the H. cunea. The experiment was conducted with four replications, 10 larvae individuals in each. Mortality of H. cunea were reported daily, over 12 days. At the end of 12 th day, among the isolates of entomopathogenic fungi, the TR-05 isolate of the L. muscarium ranked the highest mortality by 93.9% rate. Effect of the other isolates of L. muscarium varied between 72.7% and 90.9%. The TR-01 isolate of the S. lamellicola showed effect of 57.6%, and the TR-02 isolate showed effect of 78.8% mortality. Effects of all the isolates used in the study were differed from the control (P<0.05). Based on LT 50 and LT 90 values, the most effective isolate was identified as TR-04 (5.64/day and 9.38/day, respectively). It can be concluded that, the isolates of L. muscarium was found quite effective and it could be a promising agent for controlling this pest in the field in the future.