AbstractThis study aimed to determine the effectiveness of Bacillus subtilis in controlling ascospore development of Aspergillus niger, in vitro.A. niger ascospores were discharged into petri dishes with water agar (T1) and into petri dishes with water agar and B. subtilis (T2). The lengths of the germ tubes emerging from the ascospores were measured after forty-eight (48) hours.

Results of the in vitro test showed that the length of the germ tubes of the ascospores of M. fijiensis in T2 (________ m) was significantly shorter than that observed in T1-control (________ m).

It was concluded that B. subtilis is effective in controlling ascospore development of A. niger.

Introduction

Bacillus subtilis(Bacillaceae)is a widespread bacterium found in soil, water, and air. It controls the growth of certain harmful bacteria and fungi, presumably by competing for nutrients, growth sites on plants, and by directly colonizing and attaching to fungal pathogens. When applied to seeds, it colonizes the developing root system of the plants and continues to live on the root system and provides protection throughout the growing season. Aspergillus niger (Trichocomaceae)is a fungi thatcan cause the rotting of numerous fruits, vegetables, and other food products. It causes root curling and top deformation in plants, thus causing substantial economic losses due to spoilage. B. subtilis has the capability to shorten the germ tubes of mycotoxins, which A. niger is one. The aim of this study is to test the effectivity of B. subtilis to reduce or remove the effect of A. niger on Mangifera indica (Anacardiaceae), particularly black molds.M. indica (Mango) one of the commercially produced in the world, but it is also very susceptible to diseases which A. niger is one, with the help of the B. subtilis the amount of damage A. niger can cause to mangoes and other plants, will be drastically reduced, increasing the harvest and production of mangoes.

Chapter 3METHODOLOGY

Phase I: In Vitro testGathering of specimens: Five (5) leaves from the Cavendish Banana variety with black Sigatoka, as indicated by necrotic burnt tissue, were collected from Bureau of Plant Indusstry (note: the leaves have not experienced rain for three days). The leaves were cleaned with dry tissue paper and it was made sure that the leaves did not get wet. The samples were incubated in a plastic bag with a moist towel for 48 hours at room temperature. The bag was sealed in order to maintain the moisture in the bag.

Preparation of the Broth Culture of Bacillus Subtilis: One hundred ml of distilled water was mixed with 2.8 grams of nutrient broth in Erlenmeyer flask. The mixture was heated and stirred until the solution is clear. The broth was then sterilized in the oven for 15 minutes at 121 C. The flask was soaked in the water bath until the broth cooled. Each 20-ml sterilized test tube was poured with 15 ml of broth. Bacillus subtilis was then inoculated into the test tube and were incubated at 30 C for 24 hours.

Preparation of Treatments: Water Agar, a culture medium of 2% water agad formulation, was prepared, For every 1000 ml of water, there was 10 g of agar. For T1, 5 petri dishes each with 25 ml 2% water agar were prepared. For T2, 5 petri dishes with 25 ml 2% water agar were poured plated with 2 ml of broth culture containing Bacillus subtilis.

Bacillus subtilis as a biological control agent of Mycosphaerella Fijiensis causing Black Sigatoka in Bananas.This study aimed to determine the effectiveness of Bacillus subtilis in controlling Development of Mycosphaerella fijiensis in vitro, and to compare its effectiveness with that of different fungicides.M. fijiensis ascopores were discharged into petri dishes with water agar (T1) and into petri dishes with water agar and B. Subtilis (T2). The lengths of the green tubes emerging from ascopores were measured after forty-eight (48) hours. In the field, Bacillus subtilis at 80 ml and 40 ml/lt water, Dithane, Daconil, bumper and Bankit were sprayed on different leaves. Effectiveness was measured by the number of days after treating the symptoms of the disease first appeared. Results of the in vitro test showed that the length of the germ tubes of the ascopores of M. Fijiensis in T2 (0.3066672) was significantly shorter than that observed in T1-control. In the field test, the appearance of the symptoms were most delayed by Bankit and Bumper while there was no significant difference between the number of days the symptoms appeared in the leaves sprayed with B. Subtilis at 80 ml and 40 ml/lt water, Dithane and Daconil.It was concluded that B. Subtilis is effective in controlling ascospore development of M. Fijiensi and that bumper and bankit are the most effective in delaying the appearance of the symptoms of M. Fijiensi while Bacillus subtilis at 80 ml and 40 ml/lt water, Dithane and Daconil are equally effective in delaying the appearance of the symptoms of M. fijiensi