diff --git a/src/main/java/ch/zhaw/gartenverwaltung/io/JsonTaskList.java b/src/main/java/ch/zhaw/gartenverwaltung/io/JsonTaskList.java
index b5a0a49..493ebd4 100644
--- a/src/main/java/ch/zhaw/gartenverwaltung/io/JsonTaskList.java
+++ b/src/main/java/ch/zhaw/gartenverwaltung/io/JsonTaskList.java
@@ -87,10 +87,11 @@ public class JsonTaskList implements TaskList {
             loadTaskListFromFile();
         }
 
-        for (Task task :
-                taskMap.values()) {
+        List<Task> temptasks = taskMap.values().stream().
+                filter(task -> { return task.getCropId() == cropId;}).toList();
+        for (Task task : temptasks ) {
             if (task.getCropId() == cropId) {
-                taskMap.remove(task);
+                taskMap.remove(task.getId());
             }
         }
         writeTaskListToFile();
@@ -113,6 +114,7 @@ public class JsonTaskList implements TaskList {
         if(task.getId() == 0) {
             task.withId(idProvider.incrementAndGet());
         }
+        taskMap.put(task.getId(),task);
         writeTaskListToFile();
     }
 
diff --git a/src/test/java/ch/zhaw/gartenverwaltung/io/JsonTaskListTest.java b/src/test/java/ch/zhaw/gartenverwaltung/io/JsonTaskListTest.java
index 37cd3a4..a41c973 100644
--- a/src/test/java/ch/zhaw/gartenverwaltung/io/JsonTaskListTest.java
+++ b/src/test/java/ch/zhaw/gartenverwaltung/io/JsonTaskListTest.java
@@ -50,13 +50,13 @@ public class JsonTaskListTest {
     @Test
     @DisplayName("Add task.")
     void addTask() {
-        Task task = new Task("Testtask", "This is a test Task.", LocalDate.parse("01.05.2022", formatter), 1);
+        Task task = new Task("Testtask", "This is a test Task.", LocalDate.parse("2022-05-01", formatter), 1);
         try {
             testDatabase.saveTask(task);
             List<Task> taskList;
             try {
-                taskList = testDatabase.getTaskList(LocalDate.parse("30.04.2022", formatter),
-                        LocalDate.parse("31.05.2022", formatter));
+                taskList = testDatabase.getTaskList(LocalDate.parse("2022-04-30", formatter),
+                        LocalDate.parse("2022-05-31", formatter));
             } catch (IOException e) {
                 throw new RuntimeException(e);
             }